The licensee of the Farthings in Blackburn is demanding an apology after 50 officers raided her pub at 7.30pm last Friday and left empty-handed.
The raid included support unit teams and dog patrols as part of Operation Converge, to crack down on drug crime across the county.
Two men were detained for a drugs search but were released without charge.
"It was totally over the top," licensee Julie Hanson told the Lancashire Telegraph.
"The raid has ruined our reputation because everyone is talking about us and they think we're drug dealers which is totally untrue."
Chief inspector Peter Lawson said: "We will not tolerate drugs being sold and used in licensed premises and where we have information that this is happening we will take robust action."
Geoff Sutcliffe, president of the Federation of Licensed Victualler's Association and Blackburn host, said: "We have to support the police if they think drug dealing is happening.
"In the last 12 months we've been having community meetings in different areas with the police, who act on reports."