In general, two cold medicines are not recommended to be mixed, because many cold medicines have the same ingredients, usually containing paracetamol or acetaminophen, paracetamol can relieve nasal congestion, runny nose, and also relieve mild sore throat, but has a certain central depressant effect, which can easily make people drowsy. If two cold medicines are taken at the same time, it is easy to cause the phenomenon of paracetamol overdose, which can lead to mental depression and drowsiness. In addition, acetaminophen is a non-steroidal anti-inflammatory drug, with antipyretic, analgesic and anti-inflammatory effects, but also has a certain damage to the gastric mucosa. So when you take two kinds of cold medicine, it will lead to acetaminophen overdose, which will easily cause some damage to the gastric mucosa, and acute gastric bleeding or gastric mucosal damage will occur. However, if the cold medicine of the Chinese class is mixed, it is not very harmful, because often the content of western medicine is less.