Consult a health care practitioner prior to use if you are pregnant or breastfeeding or if you are taking carbidopa or drugs/supplements with serotonergic activity. These may include, but are not limited to, L-tryptophan, S-adenosylmethionine (SAMe), St. John's wort, antidepressants, pain killers, over the counter cough and cold medication containing dextromethorphan, anti-nausea medication and anti-migraine medication. Consult a health care practitioner if symptoms persist or worsen. Discontinue use and consult a health care practitioner if you show signs of weakness, oral ulcers, or abdominal pain accompanied by severe muscle pain, or if you experience skin changes. Do not use if you have scleroderma. Exercise caution if operating heavy machinery, driving a motor vehicle or involved in activities requiring mental alertness. Some people may experience diarrhea, nausea, vomiting, abdominal pain and drowsiness.