DIM is a natural extract of cruciferous vegetables. The acids in your stomach turn indole-3-carbinol, a phytochemical in cruciferous vegetables into DIM. Once it's absorbed into your system, DIM can balance the activity of different types of estrogen. 

In the right amount, DIM is considered safe and nontoxic. In one study on 353 women, patients received 150mg of DIM per day for six months. The side effects were minor and transient. The most common side effect was a temporary darkening of the urine. About one-fourth of the women experienced an increase in bowel frequency, while 18 percent had headaches or gas. Less common side effects included nausea, diarrhea, and a skin rash. Thirteen percent of the women reported changes in their menstrual cycle when they took DIM. 

As with any supplement, consult with your physician before consumption if you have any pre-existing medical condition or taking prescription medication.
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