From basil to thyme, dried spices and fresh herbs jazz up foods and beverages and reduce reliance on salt and fats.

Cooks find today's grocery shelves filled with traditional dried spices and herbs, and more seasonings for Latino and Asian cuisine. Once relegated to summer, fresh herbs — among them, dill, oregano, cilantro and mint — abound in produce aisles year-round.

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Dried spices and fresh herbs jazz up foods and beverages and reduce reliance on salt and fats.

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For hundreds of years, herbs and spices have been used for medicinal purposes. Advocates of holistic and alternative medicine say that herbal remedies and supplements offer advantages over traditional medicine.

But whether dried, fresh or sold as supplements, herbs and spices can be detrimental if they interact with other medicines. Like much of life, moderation is the key to good living. Check with a physician before using any herbal or dietary supplements for medicinal purposes. Aromatic cinnamon, enticing nutmeg or fresh pungent garlic add flavor to food, but they can have adverse health consequences if used in excess. Herbal or dietary supplements can interact with prescription medicines. Here's what you need to know:

• Watch for drug interactions: "It depends on who's taking them and what other medications they are on because there is a lot of interaction that affects their health," said Dr. Glen Daughtry, a physician on the staff of the Holy Spirit Health System's Devonshire Family Health Center in Lower Paxton Township, Pa.

• Adults only: Herbal supplements generally should not be taken by anyone under 18, and, unless directed by a physician, spices, herbs and supplements should not be ingested by pregnant women or nursing mothers.

• Tell your doctor about herbal supplements: "A lot of people will not tell their doctors if they are on these supplements and herbs because the people think they are natural, that it's just like food. That's not true," Daughtry said.

• Some herbs make symptoms worse: Garlic is reputed to be a cholesterol-fighting herb, but it can affect the clotting of blood. "If people are on blood thinners and they say 'I want to take a lot of garlic because it's good for me,' and they might be taking vitamin E, I get real concerned," he said.

Adding aspirin to the mix is especially dangerous if the patient is scheduled for surgery.

Licorice syrup, derived from the roots of the licorice plant, is believed to have anti-oxidant, anti-inflammatory and anti-ulcer properties, but it can increase blood pressure. "Licorice can cause fluid retention and hypertension," Daughtry said.

• Serving size matters: A consumer might not know what dosage he is taking because the strength of the raw product varies. "The amount of licorice can vary from 7 to 10 percent depending on growing conditions," he said.

Consumers should investigate where the raw ingredients are grown and processed, especially if the origin is out of the United States.

Cinnamon and nutmeg can irritate sensitive stomachs. Skin irritations have been found among workers at cinnamon production plants.

• Moderation, moderation, moderation: ''If people eat a well-balanced meal and are active, I think they are getting a pretty good dose of what they need to maintain a good healthy lifestyle," Daughtry said.

SPICY TIPS

Spices are derived from the roots, bark, buds and fruits of plants. Herbs are taken from the leaves.

Here are some questions and answers about spices and herbs.

When should spices and herbs be added to food? Fifteen minutes before the end of cooking for ground spices, one hour before the end of cooking for whole spices and at the end of cooking time for fresh herbs.

What is the shelf life of dried spices and herbs? Three to four years for whole spices and seeds, two to three years for ground spices, one to three years for leafy herbs and one to two years for seasoning blends. If a herb or spice smells bad or has an off color, discard it.

How should fresh herbs be refrigerated? Place bunches with their stems in water. Place loose leaves in perforated plastic bags with dry paper towels.

What is the ratio of fresh to dried herbs? Three to one. Dried herbs are more concentrated. Use 3 tablespoons of fresh to 1 tablespoon dried.

Where can I get information about the medicinal properties of herbs and spices? The National Institutes of Health's National Center for Complementary and Alternative Medicine lists common herbs and spices and the latest studies on their efficacy; nccam.nih.gov. The Mayo Clinic also has information about herbal supplements at www.mayoclinic.com

Where can I research consumer health products and recalls? ConsumerLab.com provides independent test results and information to help consumers evaluate health, wellness and nutrition products, at www.consumerlab.com.