Can I take this pill on shabbos? It has a word on it that will be erased as it dissolves in the stomach. The letters are somewhat imprinted onto the pill and cannot be washed off. It is not an essential medicine so it need not be taken specifically on shabbos. I just wonder if there is an issue with this kind of a pill.
Your question is really theoretical, because if the pill cannot be taken on Shabbos, the question will not come up. However even if the pill would be one that may be taken on Shabbos, we don’t have to worry about our intestines erasing the words on the pill, for a number of reasons. First of all, you have no interest in erasing the words, and you have nothing out of it, (פ”ר דלא ניחא ליה) secondly it isn’t the normal way of erasing, ( כלאחר יד) additionally your action, which is swallowing the pill only causes the action to take place later on, (גרמא).