Nearly 200l of potentially deadly laughing gas was stolen from Cobham Health Centre last week.
Thieves broke into the day centre surgery in Portsmouth Road, sometime between 7pm on Monday, December 2, and 4am on Tuesday, December 3.
The burglars broke into the store room and stole four 40l cylinders, which are 5ft long, and three 5l cylinders all containing nitrous oxide.
Nitrous oxide is more commonly known as laughing gas and can be potentially fatal when not used for its correct purpose.
It has, however, become the second most popular 'legal high' used by young party-goers, often inhaled through balloons. It is illegal to sell to anyone under 18 if it is thought it will be inhaled.
The depressant-type drug slows down brain and body response and can make people feel dizzy, have hallucinations and create sound distortions.
The gas can also cause unconsciousness or death from lack of oxygen, with the risk of fatality greater if the gas is inhaled in an enclosed space.
In August 2012, Joseph Benett, 17, from north London, suffered a cardiac arrest after inhaling nitrous oxide. He fell into a coma and died one month later.
In July this year, Home Office figures revealed that the drug, also known as hippy crack, is the second most popular legal high among young people, with one in 16 people aged 16 to 24 admitting to have using it.
Prince Harry is among those seen using the drug in the past.
Surrey Police are investigating the incident and have issued an appeal for witnesses to come forward.
PC Paul Grinter, investigating, said: “These canisters are very heavy and distinctive as they are white with blue shoulder markings.
“Due to the weight and cumbersome nature of these cylinders it is most likely that more than one person would have been involved in the theft. They would also have needed some substantial form of transport, possibly a van to move them.
“I urge anyone who may have seen or heard anything suspicious around the time of this incident to contact us by calling 101 as the information may prove vital to the investigation.
“Perhaps you may have approached to buy or use the nitrous oxide which could prove medically dangerous if used inappropriately.
“It's also possible that the cylinders have already been dumped somewhere and we ask anyone who may have seen any matching this description to contact us.”
Anyone with information should contact PC Paul Grinter at Surrey Police on 101, quoting reference 45130003561 or Crimestoppers on 0800 555 111.