All drugs cause some side effects. However, some cause minor and some cause major side effects. Common side effects of using Lamisil are: A headache, Diarrhea, Rash, Upset stomach, Abnormal liver function tests, Itching, Change in taste, Nausea, Abdominal pain, Gas Liver disease (possibly fatal), Persistent nausea, Vomiting, Loss of appetite, Abdominal pain, Dark urine, Yellowing eyes/skin, Allergic reaction, Rash, Itching, Swelling (especially of the face/tongue/throat), Severe dizziness, Trouble breathing