Hi! I am a post-heart transplant patient and am very careful reading labels. I just went to the pharmacy to pick up some cough lozenges and Halls drops - citrus flavor - contains grapefruit juices. In very fine print you can see what fruits are used in the product. La Croix sparkling water also has a grapefruit flavor and while it may read artificial/natural flavors, I will stay away from that. I don't want anything affecting my anti-rejection meds and I don't want a misread on my labs and have to take more or less meds as an erroneous result. Please be careful and a bit overly cautious.