Ecstasy: Three Tales of Chemical Romance

You know that revolting scene in Trainspotting where Renton takes a dive into the toilet? Readers might get the same sickening jolt from reading the warped fictional triptych, Ecstasy: Three Tales of Chemical Romance, by Irvine Welsh (whose previous books The Acid House and Marabou Stork Nightmares will soon follow his Trainspotting into film). That's because the first two unevenly witty tales — ''Lorraine Goes to Livingston,'' about a romance novelist who gets revenge on her porn-addicted husband by writing raunch, and ''Fortune's Always Hiding,'' which chronicles the battle waged by two armless victims of Tenazadrine, a drug that caused gross birth defects, against the corporate honchos who marketed it — are propelled by tedious shockeroos like necrophilia and chain-saw dismemberment. Only ''The Undefeated: An Acid House Romance'' — about an unhappily married woman who undergoes a sensual awakening via Ecstasy and a cute slacker — displays the kind of hilarious dialogue and inventive kaleidoscopic storytelling that is signature Welsh. B-