The spot, created by DDB London, shows a brown blob rolling down a busy street in a town. Some people start to run in terror, but others turn around and dive into the blob of Marmite, eating it and smiling.
The spot uses the long-running slogan "You either love it or hate it".
Six complaints were received by the Advertising Standards Authority about the ad. Four parents complained that their children had refused to watch television after the ad was shown, and another two said that it had given their children nightmares.
All of them said that their children, aged between two and three years old, had been "terrified" by the spot, which had originally been cleared for viewing without any time restrictions.
In light of the complaints, Marmite revised its advertising schedule to ensure that the ad was not shown around children's programmes or on children's channels.
It argued that an ex-children restriction would be unnecessary, because it was only very young children who had been adversely affected, but that this would prevent it from screening the ad on some channels that restrict advertising in shows that attract a high audience of children, such as ITV's 'Pop Idol'.
However, the ASA has slapped an ex-children restriction on the spot.
"We considered that the ex-kids restriction was designed to exclude advertisements from programming made for or specifically targeted at children, but that if broadcasters chose to apply the restriction in a wider sense that was their prerogative," the watchdog said.
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