Hours after Dave Stellick arrived on a flight from Atlanta, he was in a drug store looking for cold and flu medication.

"I was sitting next to a guy on the plane that was sneezing and I was just thinking, `I know I'm going to get sick in a week,"' said Stellick, 36, of Atlanta. "Too much traveling, too much flying sitting next to sick people."

Nyquil, Tylenol, Robitussin, Advil, Tamiflu: With the flu vaccine (search) running out and the number of flu cases climbing, drug stores and online companies around the country are reporting brisk sales of both over-the-counter remedies and prescription drugs in the past few weeks.

"I'd say this is the most severe year we've seen in quite a number of years," said Ken Chao, pharmacy director for the King Soopers (search) grocery chain.

The number of states hit hard by the flu has doubled to 24 over the past week and now includes most of the western half of the country. Nationwide, at least 20 children have died in what could become the worst flu season in years.

Drugstore.com (search) reported a 46 percent increase in over-the-counter flu products in the past five weeks, compared with the same period of 2002, said Rasa Perhanian, who oversees sales of cough, cold and flu products.

"Last week alone, I sold 50 percent more product than the week before," she said.

Walgreen Drug Stores and Wal-Mart reported a rise in sales of flu drugs in the past week, but gave no figures.

Among prescription drugs, demand has picked up for Tamiflu — which can prevent or relieve the flu — and for FluMist, a nasal version of the flu vaccine, according to the makers of the medicines. They gave no numbers.

Some stores have reported intermittent shortages of certain products.

Jake Mossman, owner of a Taos, N.M., pharmacy, said the number of inquiries he has had from customers advice on the flu has doubled in a two-day period.

"Over-the-counter and prescription volume has gone up tremendously in the same time frame, so I think there are people who are definitely ill," he said. "We haven't gotten to the point where we've run out of anything other than the prescription anti-virus have been hard to get."

Ben's Best kosher deli in New York City first offered its "cold and flu baskets" with chicken soup and tissues in 1986 as a way for customers to comfort sick friends. Deli owner Jay Parker estimated he sold 350 baskets last year, and expects more of the same this year. The basket includes a mug that says "Jewish penicillin."

"It's just somebody's way of showing the next person they care about them," he said.

Parker, who is married to a pharmacist, said: "She gets you on the prescription side. I get you on the holistic side."