When used for short periods, Moxifloxacin is a safe drug but it does have a few rare side effects. Mild side effects of the drug include stomach cramps, nausea, headache, dizziness, difficulty sleeping, diarrhea and bloating. In most cases the symptoms rapidly subside but if they persist, one should notify the local physician. In very rare cases, Moxifloxacin can also induce sensitivity to sunlight, cause easy bruising, tiredness, or yellow discoloration of the skin. When the drug is taken for a long time, it may also induce a severe diarrhea and stomach cramps.