The management of the public catering establishment must compensate the full cost of the medication, which was spent on treatment, if you prove that you were poisoned in the establishment, and not at home. In this case, you should also demand compensation for the moral damage that was caused to you. It will be easier to prove the fact of poisoning if you have a receipt that will confirm your stay at the restaurant, which is a direct contract with the other party. But if you left the check at the institution, lost it or threw it away, don't worry. In this case, you should enlist the support of witnesses to your visit to the establishment and ordering specific dishes. Next, you need to get medical documentation that will confirm the fact of food poisoning.
Before going to court, try to settle the issue with the administration of the institution in a pre-trial procedure. Write a statement in the name of the restaurant management to comply with the general rules established by the record keeping, state in the statement the circumstances that happened to you at the establishment, be sure to attach evidence that confirms your words (a medical certificate from a health care institution about poisoning ).
If it was not possible to come to an agreement "peacefully", it is necessary to contact the territorial body of the State Production and Consumer Service. In the event that the catering establishment refuses to compensate you for the expenses related to the poisoning and does not admit its fault, you have the right to apply to the court for the protection of your rights and interests.