Echinacea purpurea therapy for the treatment of the common cold: a randomized, double-blind, placebo-controlled clinical trial. Echinaforce and other Echinacea fresh plant preparations in the treatment of the common cold. A randomized, placebo controlled, double-blind clinical trial. Efficacy of Echinacea purpurea in patients with a common cold. A placebo-controlled, randomised, double-blind clinical trial. A randomized controlled trial of the effect of fluid extract of Echinacea purpurea on the incidence and severity of colds and respiratory infections. A proprietary extract from the echinacea plant (Echinacea purpurea) enhances systemic immune response during a common cold. Efficacy of a standardized echinacea preparation (Echinilin) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trial. Treatment of the common cold with unrefined echinacea. A randomized, double-blind, placebo-controlled trial. Echinacea root extracts for the prevention of upper respiratory tract infections: a double-blind, placebo-controlled randomized trial. The efficacy of echinacea compound herbal tea preparation on the severity and duration of upper respiratory and flu symptoms: a randomized, double-blind placebo-controlled study.
Echinacea purpurea stimulates the immune response and is promoted to reduce symptom severity and the duration of upper respiratory tract infections. We sought to determine the efficacy of a standardized preparation of E purpurea in reducing symptom severity and duration of the common cold.
                A randomized, double-blind, placebo-controlled design was used. Patients received either 100 mg of E purpurea (freeze-dried pressed juice from the aerial portion of the plant) or a lactose placebo 3 times daily until cold symptoms were relieved or until the end of 14 days, whichever came first. Symptoms (sneezing, nasal discharge, nasal congestion, headache, sore or scratchy throat, hoarseness, muscle aches, and cough) were scored subjectively by the patient and recorded daily in a diary. Kaplan-Meier curves were used to estimate the survival function of time to resolution in each group. The Wilcoxon rank sum test was used to compare time to resolution between the 2 groups.
                One hundred twenty-eight patients were enrolled within 24 hours of cold symptom onset. Group demographic distribution was comparable for sex, age, time from symptom onset to enrollment in the study, average number of colds per year, and smoking history. No statistically significant difference was observed between treatment groups for either total symptom scores (P range,.29-.90) or mean individual symptom scores (P range,.09-.93). The time to resolution of symptoms was not statistically different (P =.73).
                Some studies have concluded that Echinacea effectively reduces the symptoms and duration of the common cold. We were unable to replicate such findings. Further studies using different preparations and dosages of E purpurea are necessary to validate previous claims. The aim of this randomized, double-blind, placebo controlled study was to investigate the efficacy and safety of different doses and preparations of Echinacea purpurea in the treatment of common cold. 246 of 559 recruited healthy, adult volunteers caught a common cold and took 3 times daily 2 tablets of either Echinaforce (Echinacea purpurea-preparation from 95% herba and 5% radix), Echinacea purpurea concentrate (same preparation at 7 times higher concentration), special Echinacea purpurea radix preparation (totally different from that of Echinaforce) or placebo until they felt healthy again but not longer than 7 days. The primary endpoint was the relative reduction of the complaint index defined by 12 symptoms during common cold according to the doctor's record. Echinaforce and its concentrated preparation were significantly more effective than the special Echinacea extract or placebo. All treatments were well tolerated. Among the Echinacea groups the frequency of adverse events was not significantly higher than in the placebo group. Therefore, Echinacea concentrate as well as Echinaforce represent a low-risk and effective alternative to the standard symptomatic medicines in the acute treatment of common cold. Common colds are one of the most frequent acute illnesses with major economical impact. Echinaceae purpureae herba (Echinacin, EC31J0) has shown promising results in the relief of common cold symptoms and the time taken to improvement compared to placebo. This study was aimed to confirm these findings by performing a randomised, double-blind, placebo-controlled clinical trial. A total of 80 adult male or female patients with first signs of a cold were recruited. The number of days of illness with a complete picture of the common cold (defined by the modified Jackson score of at least 5 points and experience of rhinorrhea and/or a subjective sensation of having a cold) was the primary end-point. In the verum group the median time of illness was 6.0 days compared to 9.0 days in the placebo group, assigning zero time for patients without a complete picture (one-sided p = 0.0112). EC31J0 was well tolerated and clinically effective in alleviating symptoms more rapidly than placebo in patients with a common cold. Fluid extracts of Echinacea purpurea are widely used for the prevention and treatment of colds and respiratory infections, although the clinical efficacy of this agent has not been proven.
                A total of 109 patients with a history of more than 3 colds or respiratory infections in the preceding year were randomly assigned to receive 4 mL fluid extract of Echinacea purpurea or 4 mL placebo-juice twice a day in a double-blind manner. (One patient withdrew his consent before taking the first dose of the allocated medication; thus, only 108 patients were included for analysis.) The incidence and severity of colds and respiratory infections were determined during 8 weeks of follow-up, based on patient reported symptoms together with findings on physical exam. The severity of each infection was graded by the investigators. Relative risks (RR) and 95% confidence intervals (CI) were estimated.
                During the 8-week treatment period, 35 (65%) of 54 patients in the Echinacea group and 40 (74%) of 54 patients in the placebo group had at least one cold or respiratory infection [RR = 0.88; 95% CI (0.60, 1.22)]. The average number of colds and respiratory infections per patient was 0.78 in the Echinacea group, and 0.93 in the placebo group [difference = 0.15; 95% CI (-0.12, 0.41), P = 0.33]. Median duration of colds and respiratory infections was 4.5 days in the Echinacea group and 6.5 days in the placebo group (95% CI: -1, +3 days; P = 0.45). There were no significant differences between treatment groups in the number of infections in each category of severity. Side effects were observed in 11 patients (20%) of the Echinacea group and in seven patients (13%) of the placebo group (P = 0.44).
                Treatment with fluid extract of Echinacea purpurea did not significantly decrease the incidence, duration or severity of colds and respiratory infections compared to placebo. In a previous paper, it was reported that Echinilin (Factors R & D Technologies, Burnaby, British Columbia, Canada) a formulation prepared from freshly harvested Echinacea purpurea plants and standardized on the basis of three known active components (alkamides, cichoric acid and polysaccharides) is effective for the treatment of a naturally acquired common cold. However, the mechanism by which this effect is achieved remains unknown. In the present study, Echinilin or placebo were administered to volunteers at the onset of their cold for a period of 7 days, with eight doses (5 mL/dose) on day 1 and three doses on subsequent days. Fasting blood samples were obtained before and during their colds. The decrease in total daily symptomatic score was more evident in the echinacea group than in the placebo group. These effects of echinacea were associated with a significant and sustained increase in the number of circulating total white blood cells, monocytes, neutrophils and NK cells. In the later part of the cold, the echinacea treatment suppressed the cold-related increase in superoxide production by the neutrophils. These results suggest that Echinilin, by enhancing the non-specific immune response and eliciting free radical scavenging properties, may have led to a faster resolution of the cold symptoms.
                Copyright (c) 2005 John Wiley & Sons, Ltd. Recently, echinacea has regained popularity as one of the treatments chosen most commonly by consumers with the expectation that it will reduce the severity and duration of the common cold. However, the results from a limited number of clinical trials for this application have thus far been inconclusive. This incongruity may be the result of investigators utilizing poorly standardized echinacea products, likely devoid of sufficient quantities of active constituents necessary to exert a definitive clinical effect. Therefore, a formulation containing alkamides, cichoric acid, and polysaccharides at concentrations of 0.25, 2.5, and 25 mg/mL, respectively, was prepared from freshly harvested Echinacea purpurea plants (commercially available as Echinilin, Natural Factors Nutritional Products, Inc., Vancouver, BC, Canada). The objective of this study was to test the efficacy of this highly standardized formulation in reducing the severity and duration of symptoms of a naturally acquired common cold.
                In a randomized, double-blind, placebo-controlled trial, 282 subjects aged 18-65 years with a history of two or more colds in the previous year, but otherwise in good health, were recruited. The subjects were randomized to receive either echinacea or placebo. They were instructed to start the echinacea or placebo at the onset of the first symptom related to a cold, consuming 10 doses the first day and four doses per day on subsequent days for 7 days. Severity of symptoms (10-point scale: 0, minimum; 9, maximum) and dosing were recorded daily. A nurse examined the subjects on the mornings of days 3 and 8 of their cold.
                A total of 128 subjects contracted a common cold (59 echinacea, 69 placebo). The total daily symptom scores were found to be 23.1% lower in the echinacea group than in placebo in those who followed all elements of the study protocol (P<0.01). Throughout the treatment period, the response rate to treatments was greater in the echinacea group. A few adverse event profiles were observed in both groups.
                Early intervention with a standardized formulation of echinacea resulted in reduced symptom severity in subjects with naturally acquired upper respiratory tract infection. Further studies with larger patient populations appear to be warranted. Echinacea preparations are widely used to treat the common cold.
                To assess the efficacy of dried, encapsulated, whole-plant echinacea as early treatment for the common cold.
                Randomized, double-blind, placebo-controlled community-based trial.
                University of Wisconsin-Madison, Madison, Wisconsin.
                148 registered students with common colds of recent onset.
                An encapsulated mixture of unrefined Echinacea purpurea herb (25%) and root (25%) and E. angustifolia root (50%) taken in 1-g doses six times on the first day of illness and three times on each subsequent day of illness for a maximum of 10 days.
                Severity and duration of self-reported symptoms of upper respiratory tract infection.
                No statistically significant differences were detected between the echinacea and placebo groups for any of the measured outcomes. Trajectories of severity over time were nearly identical in the two groups. Mean cold duration was 6.01 days in both groups as a whole, 5.75 days in the placebo group, and 6.27 days in the echinacea group (between-group difference, -0.52 day [95% CI, -1.09 to 0.22 days]). After controlling for severity and duration of symptoms before study entry, sex, date of enrollment, and use of nonprotocol medications, researchers found no statistically significant treatment effect (adjusted hazard ratio, 1.24 [CI, 0.86 to 1.78]). Multivariable regression models assessing severity scores over time failed to detect statistically significant differences between the echinacea and placebo groups.
                Compared with placebo, unrefined echinacea provided no detectable benefit or harm in these college students who had the common cold. To investigate the safety and efficacy of 2 extracts of echinacea for preventing upper respiratory tract infections.
                Three-armed, randomized, double-blind, placebo-controlled trial.
                Four military institutions and 1 industrial plant.
                Three hundred two volunteers without acute illness at time of enrollment.
                Ethanolic extract from Echinacea purpurea roots, Echinacea angustifolia roots, or placebo, given orally for 12 weeks.
                Time until the first upper respiratory tract infection (time to event). Secondary outcome measures were the number of participants with at least 1 infection, global assessment, and adverse effects.
                The time until occurrence of the first upper respiratory tract infection was 66 days (95% confidence interval [CI], 61-72 days) in the E angustifolia group, 69 days (95% CI, 64-74 days) in the E purpurea group, and 65 days (95% CI, 59-70 days) in the placebo group (P = .49). In the placebo group, 36.7% had an infection. In the treatment groups, 32.0% in the E angustifolia group (relative risk compared with placebo, 0.87; 95% CI, 0.59-1.30) and 29.3% in the E purpurea group (relative risk compared with placebo, 0.80; 95% CI, 0.53-1.31) had an infection. Participants in the treatment groups believed that they had more benefit from the medication than those in the placebo group (P = .04). Adverse effects were reported by 18 subjects in the E angustifolia group, 10 in the E purpurea group, and 11 in the placebo group.
                In this study a prophylactic effect of the investigated echinacea extracts could not be shown. However, based on the results of this and 2 other studies, one could speculate that there might be an effect of echinacea products in the order of magnitude of 10% to 20% relative risk reduction. Future studies with much larger sample sizes would be needed to prove this effect. The aim of this study was to determine the efficacy of an echinacea compound herbal tea preparation (Echinacea Plus) given at early onset of cold or flu symptoms in a random assignment double-blind placebo-controlled study.
                A total of 95 subjects with early symptoms of cold or flu (runny nose, scratchy throat, fever) were randomly assigned to receive Echinacea Plus tea five to six cups per day titrating to 1 over 5 days or placebo in a double-blind situation. Each participant completed a questionnaire 14 days after beginning the program. The efficacy, number of days the symptoms lasted, and number of days for change were measured with a self scoring questionnaire.
                The study period was 90 days (January 1, 1999 to March 30, 1999). There was a significant difference between the experimental group (Echinacea Plus) and control group (placebo) for all 3 questions measured: p < 0.001. There were no negative effects reported by any of the subjects in either group.
                Treatment with Echinacea Plus tea at early onset of cold or flu symptoms was effective for relieving these symptoms in a shorter period of time than a placebo.
Echinacea preparations tested in clinical trials differ greatly. There is some evidence that preparations based on the aerial parts of E. purpurea might be effective for the early treatment of colds in adults but the results are not fully consistent. Beneficial effects of other Echinacea preparations, and Echinacea used for preventative purposes might exist but have not been shown in independently replicated, rigorous RCTs.