My Dobermann, Meg, often takes a proprietary interest in any wounds that I get from messing around in the workshop, and tries to clean them up by licking them. But a few years ago, she suddenly took a lot of interest in a long-established and formerly relatively inactive and benign basal cell epithelioma on my finger. After years of inactivity it had recently started to spread actively. First she took a careful sniff at it, then gently but firmly attempted to nip it off with her teeth. I took the hint, and applied an old family remedy to the tumour (a couple of drops of the juice of Greater Celandine). Three months later the tumour had shrunk and gone.Thanks, Meg.

Several sets of adopted rescue cats (all unrelated to each other) have always washed each others' wounds. Also they wash my wounds - heh, cat scratches, accidents with the sewing machine etc.My dog (Rottweiler - now deceased) used to lick my forehead when I had rotten headaches. It worked! Relieved the pain instantly! It was the only time she ever licked me. And one of the cats washed the dog's sterilization wound for her.B.Australia

we lick our own wounds too. have you ever sucked your finger when you've bumped it? or licked a small cut? or when you have a mouth ulcer or sore tooth, somehow your tongue just keeps trying to serch it out in your mouth?I was always told that this was because saliva has healing properties.

I saw a documentary following Gorilla's that showed them getting sick with worms and at the onset they would go off in search of a specific plant and eat hordes of leaves from it. The leaves tasted horrible but noticed that they were very rough and the gorilla's where rolling them up into balls and just swallowing them whole. They speculated that the 'rough' leaves would somehow strip out the worms and a week later the sick gorilla would rejoin the clan.

The following answer has been selected and edited by New Scientist staffLicking each other's and their own wounds is the most common form of wound treatment for mammals. It is believed that such behaviour dates from the earliest days of mammals. Saliva generally is germicidal and benefits wound tissue, causing little harm to live tissue while helping to slough off or recycle dead tissue.The habit no doubt developed out of a defensive response to the pain, plus an eating response to bodily fluids and detritus. In fact, when mothers of many species lick sick cubs, if there is no improvement, it can lead to them eating their babies. Distressingly, such disruption may also lead the mother to eat the rest of the litter, especially if they are very young.Formal hygiene and treatment of illness and injury, especially of other individuals, is mainly a human behaviour. However, it depends on what you choose to call "treatment". Candidate activities among birds include dust-bathing, hiding and resting when ill, and "anting" - where they rub their feathers with ants, which then secrete antimicrobial chemicals. Various birds and mammals eat clays to counteract poisons in food, and some types of chimpanzees chew certain pungent leaves when ill. Such "medicines" may control parasitic worms. Since plants and traditions vary by region, those habits clearly get passed on as learned knowledge.Jon Richfield, Somerset West, South Africa