A man has a problem in his oesophagus, so he sometimes vomits. If he vomits in the washing basin, it will be blocked, thus he is obliged to vomit in the toilet. So is it permissible for him to do so as he finds a difficulty in going outside the house to vomit.
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
There is no harm for a person to vomit in the toilet as the vomit is impure and filthy. However, what is disliked is to despise food, from which one could benefit, by putting it in rubbish bins and the like, as this is being ungrateful about the bounties of Allaah.
Allaah Knows best.
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