Side effects: In a study of the side effects of fresh squeezed juice of E. purpurea among 1231 patients, Parnham documented unpleasant taste (1.7%); nausea or vomiting (0.48%); abdominal pain, diarrhea, sore throat (0.24%).²⁸ In clinical trials, similar side effects are reported with the addition of the following: heartburn, upset stomach, fatigue, sleeplessness, dizziness, headache, aggressive behavior, eczema, nonspecific rash, itchiness, increased hair loss, increased urge to urinate.^18,39,41,47

Adverse events: In clinical trials, Echinacea was well-tolerated. In trials involving children, the Echinacea group had higher rates of rash than the placebo group. The researchers were hesitant to attribute the rash to the herb as rash is common in childhood viral infections.⁴¹ Echinacea has rarely been associated with asthma and anaphylaxis in hypersensitive individuals.^55,56 Other allergic reactions include urticaria, erythema nodosum, itchy eyes, runny nose, chest tightness, dyspnea, bronchospasm, and upper airway angioedema.²

In Germany, 3 patients (over a 6 year period) who took Echinacea have died, one of vasculitis and another of thrombocytopenia. The herb's causal relationship remains unproven.⁵²

Echinacea did not cause significant changes in blood glucose, creatinine, protein or liver function studies over 2 months in healthy male volunteers.⁵⁰

Precautions/contraindications: The safety of Echinacea in pregnancy is uncertain.¹⁷ However, studies to date reveal no evidence for frequent adverse outcomes.⁵⁷

Interactions with disease states: Theoretically, Echinacea should be avoided by persons with progressive diseases such as multiple sclerosis (E. purpurea stimulated fibroblasts in vitro), autoimmune disorders such as lupus (due to stimulation of the immune system), HIV infection (increases interferon and tumor necrosis factor secretion- already elevated in AIDS patients), tuberculosis (roots of all three species of medicinal Echinacea contain arabinogalactans similar to those in the cell walls of Mycobacteria).⁵³

In clinical trials, exclusion criteria included diabetes, bronchial asthma, allergy, autoimmune disease, tuberculosis, leukemia, multiple sclerosis, polyarthritis, HIV infection, organ transplant, pneumonia, fungal infections, inflammatory GI disease or impairment of resorption, pregnancy or lactation, hypersensitivity to plants in the daisy family, and immunosuppressant therapy.²⁸

No studies have documented adverse effects associated with Echinacea in autoimmune or progressive disorders.⁵²

Echinacea should be used with caution in atopic individuals, especially those with an allergy to ragweed, chamomile, or other members of the daisy family.⁵⁴