The first thing I would recommend would be to try a different brand of Saw Palmetto (as it is a good choice), or try a liquid form instead of a capsule. Sometimes the form or brand of herbs can have less side effects, especially on the digestive system. If your digestion is still upset you can try a few other things as well. The herb Pygeum africanum has shown a lot of promising results in reducing inflammation of the prostate, reducing PSA levels and helping in the management/prevention of prostate cancer. In addition, omega-3 fatty acids (such as fish oils) can help, as can increasing antioxidant intake. Some studies have shown Zinc to have a protective effect on the prostate and a corresponding lowering of PSA levels as well (take Zinc with food to avoid stomach upset).