A number of months back there was much discussion about the adverse effects of nutrasweet, especially when taking Sinamet. One writer pointed out that when taking his pills with diet drinks, the pills had little effect. When he stopped using diet drinks, he had normal (favorable) reaction to the drugs. My wife (PD) has been a long time user of diet colas. After seeing the discussions on this Mailing List, she has stopped them completely and when she has tested the impact by going back to a single can (twice) she claims to have felt an adverse effect. I somewhat remember someone saying that the phenylalanine in nutrasweet blocks the efficacy of drugs that must pass through the blood-brain barrier. Hope this is helpful.