Taking three tablets of methylcobalamin is an overdose. If it is taken by mistake once in a while, it usually has little effect. If taken for a long period of time, it may aggravate the burden on the liver and kidneys and cause other diseases. Methylcobalamin has a high overall drug safety, if you take three tablets of methylcobalamin by mistake once in a while, there is generally no special effect on the body, follow the doctor’s instructions to adjust the medication, and closely observe their own situation. If overdose of methylcobalamin for a long time, it may increase the chance of adverse drug reactions, such as nausea, diarrhea and other symptoms, and may also aggravate the burden on the liver and kidneys, triggering other diseases. Methylcobalamin belongs to the endogenous vitamin B12, can enter the nerve cells, can repair the damaged nerve cells, improve nerve conduction speed. It is suitable for the treatment of peripheral neuropathy, and the specific dosage should be in accordance with the doctor’s instructions, and the dosage should not be adjusted without authorization.