Updated December 16, 2014.

Many packages of over-the-counter cough and cold medicines and decongestants say "Do not take if you have one of the following..." and then go on to list thyroid disease. You may wonder, then, if you can take these products for your cold or flu?

The reason for these warnings is the stimulant pseudoephedrine, an ingredient in some formulations of Sudafed and some cold and allergy medicines. Stimulants can be dangerous to people with active hyperthyroidism, as they can add strain to an already taxed heart and high blood pressure found in hyperthyroidism.

What about people with hypothyroidism? Can you take these types of medicines? This is something that needs to be decided, but generally, it is not recommended that people with thyroid problems take any products with pseudoephedrine or natural ephedra, ingredients that are sometimes found in natural weight loss, energy and cold remedies. There are anecdotal reports of people with thyroid disease becoming extra-sensitive to stimulants like caffeine, pseudoephedrine or ephedra.

As far as over-the-counter medicines, you might want to ask your doctor about using a product like Coricidin HBP, a cold remedy made specially without stimulating ingredients. You can also consider trying some of the natural suggestions described later in this article.

Alternatives, Vitamins and Supplements for Cold and Flu?

There are a number of alternative remedies that you can try to help with cold and flu.

Noted alternative practitioner Andrew Weil, MD suggests vitamin C, garlic, echinacea, and the herb astragalus -- among other natural remedies -- to help boost the immune system during flu season.

Italian researchers also found that ginseng, when given throughout the season to people who had flu shots, reduced the cases of flu, and raised the activity rate of immune cells that fight infections.

When you're in the midst of the flu, besides plenty of rest, fluids, and good nutrition, there are some additional alternative medicine approaches that some experts recommend.

Some other natural approaches that may be helpful for cold and flu include the following:

• Elderberry -- Elderberry apparently works by strengthening the cell membrane so a virus cannot penetrate it. It also appears to inhibit the enzyme that viruses use to weaken the membrane. About.com's Alternative Medicine site has more information on elderberry.
• Vitamin C -- Though the recommended daily dosage of vitamin C is usually no higher than 100 mg/day, some experts believe that as much as 1 to 6 grams (1000 - 6000 mg) of vitamin C per day may may be helpful during illness, and in particular, help reduce the duration of a fluvirus. The suggested dosage would be 1000 mg every 2 hours, unless diarrhea or gas occurs.
• Zinc Lozenges -- Over-the-counter zinc lozenges, if take at the onset of symptoms, may help reduce the effects of a flu or cold.
• Oscillicoccinum -- This homeopathic treatment may help with flu symptoms, particularly when taken right away after the onset of symptoms.
• Garlic - Garlic has natural antibiotic and antiviral properties, and some experts suggest a daily high allicin content garlic supplement which should begin during the first six hours of cold and flu symptoms.
• Camu-camu - The Amazonian rainforest fruit, rich in vitamin C, may also help combat viruses.

<sub>Sources:
Weil, Andrew. "12 Cold-Weather Remedies," DrWeil.comOnline

Scaglione, F et.al. "Efficacy and safety of the standardised Ginseng extract G115 for potentiating vaccination against the influenza syndrome and protection against the common cold" Drugs Exp Clin Res 1996;22(6):338.</sub>