Scientists have injected the acetic acid and mustard oil to the mice to measure the facial expression and it was successful to collect some research related information.

The research was held for the first time by the scientists in order to catch the scale of pain of the mice depending on facial expression. This research was named "mouse grimace scale" or "MGS".

Jeffrey Mogil professor of MC Gill University and some of his colleagues have carried out an observation to find out when exactly the rodent hurts. They recorded the facial expression before and during the time of injecting the painful substances.

The substances includes of acetic acid, mustard oil and the capsaicin. This was delivered into the stomach of the mice.

The researchers have informed that the results of this MGS will very soon be developed and it can show path for the new analgesics for human as well. Doctors and nurses routinely using this scale to find out the pain in each individual those are unable to communicate verbally in most of the medical cases.