When the incident occurred, the restaurant should have been notified and a report of the incident taken by the restaurant so that the restaurant cannot subsequently claim that the chemical poisoning may have occurred elsewhere.Your friend should file a personal injury claim with the restaurant's insurance carrier.  When your friend completes his medical treatment and is released by the doctor, he should obtain his medical bill, medical report, and if applicable, documentation of any wage loss.  Your friend's personal injury claim filed with the restaurant's insurance carrier should include these items.  Compensation for the medical bill is straight reimbursement.  The medical report will document the nature and extent of your friend's injury and will be used to determine compensation for pain and suffering, which is an amount in addition to the medical bill.  Compensation for wage loss is straight reimbursement.If the case is settled with the restaurant's insurance carrier, NO lawsuit is filed.  If your friend is dissatisfied with settlement offers from the insurance carrier, he should reject the settlement offers and file a lawsuit for negligence against the restaurant.  If the case is NOT settled with the restaurant's insurance carrier, your friend will need to file his lawsuit for negligence against the restaurant prior to the expiration of the applicable statute of limitations or he will lose his rights forever in the matter.