The man claims he had his wallet and mobile phone taken when he fell at around 9.30 pm in Midvale Road in St Helier.
Police say some people helped him before the ambulance arrived to take him to A&E and they now want to speak to them and anyone else who may have seen what happened.
You can call them on 612612 or contact Crimestoppers anonymously on 0800 555 111.