Dea CAT: tenant uses the rental property to operate business, wh

I have a rental property which is rented to a couple whith 3 kids.  the wife is a pharmacist,  in order to take care of family,
she is not working outside, in stead, she is registering as a licensed licensed pharmacist and opereated a personal business in the property. this is breaking our rental contract.  She pays rental on time.  what should I do?  should I terminate the rental with her, or keep as it was, or should I inform her that it is not allowed to do business in property. but how can I prevent her to do business if she agree not to.