The characteristics of adverse drug reactions: 1, universality: all “drugs” three points of toxicity, Chinese and Western medicines are no exception; be wary of someone playing word games, “health food” is not a drug, so no toxicity; 2, specificity: vary from drug to drug; vary from person to person; 3, lagging: pre-marketing clinical trials are limited by a variety of factors (the number of people, age, disease, disease, time, etc.). Pre-marketing clinical trial research is limited by a variety of factors (number, age, disease, disease, time, etc.), only after the market gradually found, there is a quantitative process, short months and years, the emphasis on accumulation; 4, long-term: rare reactions need years, decades, decades to find a case 5, plasticity: bad things can become good; old drugs, new use; create new drugs; 6, controllable: the state, social The relevant units, including the public opinion and the news media, as well as medical units, organized and planned supervision and publicity and education, can reduce ADR to a minimum.