Severe allergic reactions occur in some people, with symptoms including hives, swelling of the mouth or throat, and difficulty breathing.

The oral use of cyanocobalamin may lead to several allergic reactions such as hives; difficult breathing; swelling of the face, lips, tongue, or throat.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Ulcers, diarrhea, swelling (inflammation) of the mouth and throat, and other conditions.

An allergic reaction might be rash, itching, swelling of the face, mouth, or throat, or difficulty breathing.

Hair loss, bleeding, swelling of the mouth and throat, and general loss of energy may follow.

A severe allergic reaction, such as swelling of the face, tongue, or throat.

It is also used for sore tonsils (tonsillitis), sore throat, swelling of the mouth and throat, fever, boils, and Crohn's disease.

The symptoms affect different areas of the body and include rashes, swelling of lips and throat, difficulty breathing, a fall in blood pressure and eventually loss of consciousness.

Comment: After having a serious cough, swelling of throat for over two weeks I was prescribed this along with an antibiotic.