Directed by Peter Farrelly, with animation directed by Piet Kroon and Tom Sito. Starring Bill Murray, Molly Shannon, Chris Rock, Laurence Fishburne, David Hyde Pierce and William Shatner.

This is a kids' film from the Farrelly Brothers starring a maverick white blood corpuscle (voiced by Chris Rock) fighting a deadly virus (voiced by Laurence Fishburne) in the body of Bill Murray. 'Who framed Roger Rabbit' was the most successful combination of live action and animation, but most subsequent attempts like 'Cool World' or 'The Adventures of Rocky & Bulwinkle' haven't quite lived up to the standards achieved first by Bob Hoskins and a rabbit. And so it goes here.

One expects lots of scatological humour from the men behind 'Dumb & Dumber' and 'There's Something About Mary' and we are duly supplied with a splash of vomit served up with a whitehead soupcon. However, in choosing to target the younger market for a change, no real attempt to disgust is attempted. Although young viewers will like the brisk pace and fast-talking hero, the standard of animation is disappointing. It seems quite slapdash – more early Simpsons than Disney.

The ideas are far from novel too – we've had the inside of a body as a vast universe before in 'Innerspace' and we've had characterisations of cells before - Woody Allen once played a neurotic sperm (a role he later reprised as a neurotic ant in 'Antz'). The corruptions and bureaucracy of human society that are duly replicated on this micro level provide much of the humour. The mayor of 'Frank City' (voiced by William Shatner) is discounting the warning signals of cold 'n' flu as nothing more than that as he tries to gain another term in office by bribing all the cells with Frank's annual trip to the Buffalo wing festival.

Despite the slightly cheap look of the film, there's much to enjoy here. Chris Rock isn't as grating as he sometimes can be, Fishburne is excellent as the villain and David Hyde Pierce plays his paracetamol tablet sidekick wonderfully. This is essentially an animated buddy cop movie that spends most of the time with Osmosis Jones trading insults with his straight-laced cold pill partner. However it's difficult to suspend disbelief, when we are yanked out of Frank's insides to the live action real world.

A more even merging of the two would have created a believable hybrid world – something which never really occurs here. This is underlined by the fact that the best scenes concern our human host, the slob single dad Bill Murray who by turns worries or embarrasses his pre-teen daughter. Murray probably can't believe his luck getting a starring role with about two day's filming, but he's worth it - as usual he shows that his generation of Saturday Night Live alumni can still teach pretenders like Rock a thing or two. Not the worst way to keep some of your own little head lice out of your hair for a few hours.

Nick McGinley