San Francisco is the latest city to take issue with Monster.
In a lawsuit filed against the company Monday, City Attorney Dennis Herrera said Monster Beverage is the "worst offender" of all the energy drinks that target children in their ads.
His legal action follows Monster actually suing Herrera last week due to his demands that it bring down the level of caffeine in its drinks.
"Our lawsuit is not a reaction to their lawsuit," Herrera says. "We were proceeding on this path in the event that we would be unable to come to a resolution."
Herrera's office began investigating energy drinks in October, as San Francisco joined New York in cracking down on beverages that many believe contain harmful substances.
New York's attorney general subpoenaed Monster and other company recently concerning how the drinks are produced and marketed, while Senators Richard Durbin (Illinois) and Richard Blumenthal (Connecticut) have consistently called on the Food and Drug Administration to investigate the safety of these drinks on young people.
Monster is also being sued by the family of a 14-year-old Maryland girl who says she passed away after consuming two 24-ounce cans of the beverage.
Monster Beverage Corp. notes that its cans warn against the drink being consumed by children, those sensitive to caffeine or pregnant women.
But Herrera counters that the company clearly takes aim at the youth in its marketing, citing the "Monster Army" website that uses toddlers as young as six to promote the brand.