The exhibition of the work of American photographer Andres Serrano at the Barbican bills itself as a retrospective. It is much less than that; for anyone with even only a passing interest in Serrano the show adds nothing to what we already know about the artist who, infamously, once dangled a crucifix in a jar of his own piss, took a photograph of it, then got into a lot of trouble with the fundamentalist moralists of the American right.

The exhibition is dividen into five sections: Abstractions and Bodily Fluids; Body and Soul; Backstage Portraits; Death and Destruction; Material and Sexual Body. The categories are tiresome. The exhibition fills The Curve at the Barbican: you walk the walk round the high-ceilinged, brightly-lit arc, then it's over.

What have you seen? Pictures of brains in plexiglass cubes, bloody, glistening hearts, near-abstractions in which the frames are filled with milk, with blood, with curdled light-show mixtures of blood and sperm. You think of ten-a-penny monochromes, Barnet Newman stripes, the red yellow and white of Mondrian. You don't really think of Mondrian or Newman, but know that Serrano wants you to.

Serrano graduated to art via a strict, New York Catholic upbringing, forays into drugs and a career in advertising. Somehow, it all shows. For a while, when he was drowning crosses and religious knick-knacks of the suffering Christ in wee-wee and milk, it appeared that he was trying to say something about the the shiftiness of symbols, the transubstantiations of the mass and of photography, making some kind of link between the altar and the darkroom. But when he started doing the same with plaster martyrdoms and mythological scenes, it became clear that these photos, the images looming in brightly tinted fog, were far more about being lurid than anything else. It is as if he got seduced by his own style.

Serrano knows how to make simple shapes within the frame, to crop the larger than life images to make you feel up close and personal. His Ku Klux Klansmen in their silly pointy penitential hoods make great shapes; so too does a picture of a nun, whose gaze is as clear as her conscience.

How was it that Serrano, whose Piss Christ shocked the moral majority, was approved access to photograph these servants of the Faith? And how did this half-Honduran, Afro-Cuban artist got to hang out with the Imperial Wizards, the Great Titans and Knights of the KKK? Charm and guile, I guess, and playing on the Klansmen's vanity.

Serrano was let into the morgue, to make his photos of the stillborn, barbecued burn victims, Jane Doe shot by the cops, Aids deaths and suicides. The morgue photos have little of the necrophiliac nastiness, say, of Joel Peter Witkin, and frequently, his pictures of dead babies have that sentimental Victorian air, not of death, but of perpetual sleep. All these images have been theatricalised in some way. Instead of death, he rubs our noses in texture, sheen, shapes, gorgeous gore, strong meat in strong light.

At the far end of The Curve we get some of his sex pictures - a portrait of a young couple, she with a strap-on dildo, he with a mildly expectant expression; a man contorting himself to perform auto-fellatio, pictures of old and youthful nakedness. Facing them, are three huge female bodybuilders, muscle-bound hormonal wrecks with pecs and frightening fingernails. Why do these people do this to themselves, you ask? Like the man trying to suck his own penis, they do it because they can.

See, its happened - I forgot to think about Serrano's work for a second, and thought only of what his images show us. In the end, the show is all surface, and looking for hidden depths does no good.

There's something dispiriting about this show, which probably couldn't make Serrano look worse if it tried. Its a quick tilt round the curve of sex, death and dressing-up. The last image is the first - the Stars and Stripes flag with a trickle of blood, a limited edition in aid of the victims of September 11th. Heavy content and a crass image: I keep thinking Serrano can do better than this, but then again, maybe he can't.

Andres Serrano: Placing Time and Evil is at The Curve, Barbican (020-7638 8891), London EC2 until December 23.