Many things in New York City induce nausea: buses spewing fumes, the 12 different perfumes they spray on you as you walk through Bloomingdale's, the new improved Times Square. It's to be expected in a place so over-stimulating, so assaulting on the senses. But let's expand the definition of "nausea" to describe a trend in visual art.

Let's expand it to include anything that causes actual changes to your body, to your very nervous system, and may include symptoms of vertigo and wooziness in addition to chills and hot flashes. It's much like Stendhal's syndrome, which afflicts a number of tourists in Italy every year, so named because the French writer was so overwhelmed by the works of art he was seeing in Florence that he had to stop and hyperventilate. Over the course of a two-week stay in New York, I became aware that I was leaving gallery after gallery with this very sickness, and that it was not entirely unpleasant.

It began in the Andrea Rosen Gallery in Chelsea, where there was a tremendously excellent show called Understanding Joshua, by an artist named Charlie White. Joshua is a deformed homunculus that White has created and photographed in a variety of social situations, sometimes whole, sometimes represented by one or another of his sickly body parts.

When he's complete, Joshua has a large, pumpkin-shaped head with a wide, lipless mouth that nearly cuts it in half. He has no nose, shallow, dark-ringed eyes, a starved ribcage with an extended belly below, and enormous hands and feet. But he's out and about in the world--at a party, on the toilet, being seduced on a couch by a voluptuous brunette. In a perfectly staged tea party, four heavily lacquered matrons in pastel outfits chat, finger their pearls, and fondle three unidentifiable sections of Joshua's skin and hair. In White's vision, Joshua is as natural to the scene as the blond tint of the ladies' coiffures. He's everyone's ugly side--the inappropriate thought, the nasty habit, the unspeakable urge. And in these large-scale photographs, he's the most real creature among the plastic-looking blondes and fleshy ex-frat boys. The effect is queasy-making, both for its truth and its aesthetic.

As good as White's show is, excellence becomes a slippery construct once your physical equilibrium is involved. We emerged from Joshua's world and went next door to Luhring Augustine, where there was a Paul McCarthy installation. This work, entitled Santa Chocolate Shop, bears all of McCarthy's trademarks: performance participants dressed in masks and costumes; gluttonous and sadomasochistic use of food; confined and nearly claustrophobic space. The installation is the stage on which the performance took place, still stained with the chocolate that, as you can see in the video, is smeared all over the performers. In one case, it's poured into the mouth of a reclining elf until it overflows and she sadly, futilely rings a bell to attract someone's attention. The sight of this choking chocolate really did make my stomach turn, giving the performance's humor a decidedly dark tint. I liked this work, but it made the rest of McCarthy's oeuvre feel redundant to me; when I got to his retrospective, I felt I had already seen enough (and one of the "stages" really did stink of old food). Once shocked, in this case, twice bored.

I had that bodily experience over and over again--dizzy in front of Bridget Riley's Op Art paintings at the Dia Center, zooming in and out of focus before Andreas Gursky's enormous photographs at MoMA. Over at P.S. 1, a show called Disasters of War pitted such imaginative horrors as envisioned by Henry Darger (compulsive murals depicting violence against moppets) against those of Jake and Dinos Chapman (gory pile-ups of action figures) and the etchings of Goya.

Provoking nausea is not just a matter of using overwhelming scale or disgusting images, although that certainly plays a part. What it means, I think, is that these artists are no longer interested in simply engaging your mind, but are determined to engage all your other senses as well. It seems to me that this is exactly what's called for in this most passive era of viewing; how well it stands up to time remains, of course, to be seen.