George Toubbeh, of Fountain Valley, claims he found two dead geckos in his can of beer.
However, Heineken said it has investigated and believes there is no merit to the claim.
The company said it holds the safety and integrity of the products it imports to the highest standards.
Toubbeh said he noticed a foul taste while drinking the beer in 2015 and became violently ill.
His lawyer said his office has done its own independent investigation and is confident the claim is credible.