SmithKline Beckman Corp. said it will reintroduce the popular cold medicine to the market in tamper-resistant caplets and capsules. The consumer drug was removed from stores in March because of tampering, along with Teldrin, an over-the-counter allergy medicine, and Dietac, a weight loss capsule. The company said it will also bring back Teldrin. But it is dropping the production of Dietac because sales have been declining. "We are absolutely confident about this return and future success of Contac," said Henry Wendt, president and chief executive of SmithKline. The company displayed a solid white caplet with 12-hour, continuous-action medication that Wendt said had the "same active ingredients and equivalent therapeutic effect" as capsules. But he said marketing surveys showed that about half of the consumers polled preferred capsules. The new Contac capsules will be completely clear with a double seal of gelatin and a new red seal so consumers can easily detect any tampering.