Herbal remedies may not reduce the symptoms of asthma, researchers have found. A team from the University of Exeter in the U.K examined the results of 17 clinical trials, which tested the impact of herbs on asthma. Six of the trials focused on traditional Chinese medicines, and eight on Indian Ayurvedic medicines. Among those that indicated some benefits, the flaws of the trials were such to cast doubt on the validity of the results. Scientists warned that none of the herbal remedies referred to is likely to be free of side effects. Some even interferes with prescribed drugs. Gingko biloba, widely considered to be medicines, has a range of possible side effects as well as the potential to interfere with anticoagulant drugs. The researchers say properly designed research is urgently needed to assess the real safety and treatment value of herbal medicines for asthma.