Can you take oscillococcinum with zoloft (sertraline)?

Yes: Oscillococcinum is a homeopathic remedy made from ducks liver. According to homeopathic principles it has been diluted 200 times so the final remedy contains no molecules of the ingredient but "contains the imprint" of the active ingredient. In other words, the final product is just plain water. As such you can take it with any medication. There is no evidence to support homeopathic theory.