TOKYO (THE YOMIURI SHIMBUN/ASIA NEWS NETWORK) - The number of people in Tokyo who were transported to hospital by ambulance in comas or other conditions after inhaling "dangerous drugs" comes up to 1,129 over the past 5½ years, including two fatalities, it was learnt on Friday.

The survey released by the Tokyo Fire Department showed that about 10 per cent of those who were taken to hospitals by ambulance due to the effects of what were believed to be dangerous drugs - quasi-legal, stimulant-like herbs - were minors.

One of them was an infant only a few months old, who was taken to a hospital after breathing the smoke of a dangerous drug that the baby's mother inhaled, the fire department said.

The number of people who received emergency transport due to dangerous drug inhalation in Tokyo peaked in 2012 at 47 times the 2009 figure, and in 2013 it was still high at 34 times the 2009 level, according to the survey.

The fire department conducted the survey for the first time in light of an incident in June this year in which a driver under the influence of a dangerous drug killed one woman and injured seven other people in the crowded Ikebukuro shopping district of Tokyo.

The survey was conducted by searching for such words as dappo (quasi-legal) and "herb" from records of emergency transportation by ambulance in and after 2009, confirming the linkage of the emergencies with dangerous drugs, department officials said.

The people transported by ambulance after using dangerous drugs in the metropolis stood at 10 in 2009 and 26 in 2010, but the figure shot up to 127 in 2011 and leaped sharply to 473 in 2012, the survey revealed.

The number of such people was 344 in 2013 and 149 in the first six months of this year, it showed.

The decline in the number of people taken by ambulance to hospitals is believed to be because many of those feeling sick after inhaling dangerous drugs apparently fail to call an ambulance as the police clampdown on dangerous drugs has become more stringent, the officials said.