Users who try Trimox find that the medication is very safe and does not usually cause side effects. However, there is some possibility of an adverse reaction. Less serious complications include nausea, vomiting, abdominal pain, vaginal discharge, headaches, itching, oral thrush, and a black or swollen tongue. Other side effects that should be reported to medical personnel include the following symptoms: clay-colored bowel movements, jaundice, chills and fevers, a decrease in urination, seizures, strange thoughts, skin blistering or peeling, watery or bloody diarrhea, abnormal bruising, weakness, confusion, loss of appetite, or dark urine.