Officers used battering rams to smash into suspects homes during simultaneous raids on two suspected drug dens.
At the first raid a man and a woman were led away in handcuffs for questioning after officers found a suspected large quantity of class A and class C drugs from the house.
They recovered what are believed to be nine blocks of cannabis resin each with a street value of £1,000 and several thousand ecstasy tablets.
Cops also seized equipment believed to be used for the growing of cannabis plants.
Officers also emerged from the house with a terrifying knife that had a multi-bladed knuckle duster for a handle. A rifle was also recovered from the property.
At the same time, only streets away, a second raid was taking place.
There officers arrested five women and three men on suspicion of possessing class A drugs with the intent to supply.
What was believed to be an imitation firearm and an air weapon were recovered from the house.
The suspects were loaded into a police cell bus before being driven away for questionning.
Specialist firearm and drugs officers were this week testing substances and weapons to certify their authentisity.
The raids were the first execution of warrants in South Yorkshire as part of Operation Impact which will target drug dealers and users during the next month.
Around 30 officers, including police dog handlers, were involved in carrying out the raids.
Chief Inspector Ian Bint, who is leading the operation, warned dealers that drugs will not be tolerated in communities.
He said: "It is a four-week operation so I'll be a lot happier at the end of the operation but as for the first two addresses I am quite happy with the progress we are making."
The initial phase of Operation Impact, in November 2005, targeted suspects and wanted people, with officers making nearly 1,000 arrests in a three-week period. Another phase of the operation in December helped reduce vehicle crime by 80 per cent around Barnsley.
South Yorkshire Police Chief Constable, Meredydd Hughes, said: "South Yorkshire Police has had some excellent success in the past year in seizing drugs involved with higher-level dealing, particularly in relation to cocaine and crack cocaine.
"We now want to concentrate some of our attention on the lower-level dealing that blights our communities and we intend to catch up with as many people involved with this as we can during February – and we will catch up with them."