The side effects of venlafaxine are relatively few, but as a biphasic antidepressant, there are mainly the following side effects after taking it: 1. It often occurs at the beginning of taking the drug, such as nausea, vomiting, dizziness, headache, or causing anxiety, irritability and other side effects, these symptoms usually disappear gradually within a week of taking the drug. 2. It may cause the problem of turning into mania, because venlafaxine is a very good 3. It may cause 5-hydroxytryptamine syndrome, that is, the serum content of 5-hydroxytryptamine is increased, causing unstable blood pressure, increased blood pressure and other side effects. It may also cause physical damage when taken for a long time, such as damage to liver and kidney function, so be sure to check liver and kidney function regularly when taking the drug for 3 months or more. All of the above side effects should be treated with caution, especially on a case-by-case basis.