The number of treatments you need depends on the type of head lice treatment you choose. With Paranix Treatment Spray, Lotion & Shampoo one treatment (including thorough combing) will be sufficient in most cases to effectively get rid of head lice. We advise you to re-check for head lice after 7 days and repeat the treatment if necessary, should you encounter any living head lice. Treating with Paranix For Long Hair requires one (overnight) application only. No matter what Paranix treatment you choose, always use sufficient product. This is vital for a successful outcome.