The Tv action man previously launched legal action against his sibling, Andrew, over his business name to ensure fans were not misled into thinking the firm was affiliated with the actor.
The dispute was eventually settled, limiting Andrew to only use the phrase "Andrew Ferrigno equipment", and requiring him to issue a disclaimer online to make it clear his company had no affiliation with his famous brother's other fitness projects.
However, Lou Ferrigno claims his sibling has violated the court order because his store sign reads "Andrew Ferrigno exercise equipment", and his web store and social media pages make no mention of the company distinction.
The actor is threatening to sue Andrew if the corrections are not made, but his sibling insists he has done nothing wrong and he cannot understand why Lou is pursuing the issue.
Andrew tells Tmz.com, "My brother has money, so why does he need to suck me dry? I am so bewildered by the fact that an actor of his stature would stoop so low as to sue his own brother twice."