General cold medicine can be metabolized from the body after 3-7 days. After taking cold medicine, the drug needs to go through four steps in the body: absorption, distribution, metabolism and excretion. The drug in the human body undergoes oxidation, reduction, neutralization, decomposition and combination under the action of liver drug enzymes, and the chemical structure is changed, and these chemical changes of the drug are mainly carried out in the liver. The metabolism time of different drugs in the body is different, and how long a drug is metabolized is determined by the half-life of the drug, which is the time it takes for the concentration of the drug entering the bloodstream to decrease by half. The half-life of each cold medicine varies in length, so the time to metabolize out of the body is also different. General cold medicine metabolism time is about 3 days, will not exceed 7 days, but the elderly, liver and kidney insufficiency of people, the drug metabolism time is long. Drinking more water during taking the medicine can speed up the metabolism of the medicine.