Interfering with how the medicine is digested and absorbed by the body. For example, milk blocks iron absorption in the stomach. Calcium found in dairy products can bind some medications, such as iron supplements and some antibiotics (Cipro and Levaquin, a quinolone.)
Pros of elongated: much more comfortable for adults. I would definitely choose it for the master bathroom. Pros of round: easier for very young children to use due to the smaller opening in the seat. Also, there are code requirements of how much foot space you need in front of a toilet.
Toilet bowls are available in round and elongated (oval) shapes. Elongated bowls are usually two inches longer than round bowls and offer additional comfort. Round bowls are generally less expensive and work well in small spaces. As with rough-in standards, make sure your space will accommodate an elongated bowl before you buy.