From my understanding of the 5-ASA family, (pentasa, asacol, salofalk) essentially its aspirin 5 times concentrated, and extra buffered to survive the trip to the digestive system, designed to alleviate inflamation. period. I've never heard of bad reaction to sun exposure as a result, and I've been taking it for a couple of years now, and I've never had a problem (mind you, I live in Canada, so sun exposure isn't typically high on my risk factor).. However, there are numerous other drugs AND many other items
..( supplements, vitamins, anti-biotics, etc., etc..) that are known to react this way. I would re-examine all other items (including some food items) for associated risk to sun exposure... And, I would check with my GP, GI & esp my pharmasist for any info...