P&G won the $19M lawsuit when the court concluded that the four had spread a false accusation that P&G subsidised Satanic cults.
The rumour had proved popular with evangelicals in the US. During the 1960s, a story began circulating that the corporation was controlled by Satan worshipers. A moon-star symbol was used by the company on many of its products from 1882 to 1985, which was considered suspect.
The stars in fact stand for the thirteen original American colonies. But the arrangement of stars in the symbol was said to secretly spell out the Revelation 13:18 "number of the beast": 666.
Without examining the facts, many people, most notably evangelicals, signed petitions against Procter & Gamble and boycotted their products in the 1980s and 1990s.
This latest case is one of several unfair competition suits P&G has brought refuting the Satanism slurs.
According to P&G, the four distributors had passed on to customers the notion that its logo - featuring a bearded man looking over a field of 13 stars - was a symbol of Satan.
"This is about protecting our reputation," said Jim Johnson, P&G's chief legal officer.
Amway pointed out that it had successfully defended itself in an earlier case brought by P&G that had been connected with the rumours.
It had also, it said, done everything it could to get the rumour stamped out.