Hi & Welcome. I can understand your concern. Avoid taking these two medications together. Taking the anti-emetic (to prevent vomiting) drug Ondansetron along with the antidepressant Zoloft can increase the risk of a less common but serious condition called the serotonin syndrome , which may include symptoms such as confusion, hallucination, convulsion, high blood pressure, increased heart rate, fever, excessive sweating, blurred vision, muscle stiffness, tremor, motor in coordination, stomach cramp, nausea, vomiting, and diarrhea. In its severe form coma and even death can occur. In addition, combining these medications can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances. Hope to have answered your query. Best regards.