Part of an ongoing series on how to use supplement and behavior-based plans to treat common maladies. To read the detailed protocol, order supplements, or download the patient resource sheets, go here to create a free patient account at Fullscript by entering your name and email address: Dr. Mark McDonald’s Fullscript dispensary


Everyone gets sick. Not everyone knows how to treat it early.

Despite what the hypochondriacs and control freaks began telling us in 2020, no one can prevent all infectious exposure. Locking yourself in your home, double-masking, racing to the opposite side of the street whenever another human being approaches—none of these practice will protect you from becoming infected by a virus. Viruses are everywhere, always have been, and always will be.

In fact, it isn’t even desirable to avoid all infection. Your immune system acts like a sentry—an early warning alert system—that activates the troops to go into battle to fight pathogen invaders. If it never encounters any enemies, it will eventually weaken and go to sleep. Then, when the inevitable invasion does arrive, it will be unprepared to fight, and your body will succumb. This is not advisable, and entirely avoidable.

In a future post, I will explain how to best prepare in advance for infectious exposures, not necessarily by avoiding them but by strengthening the body’s defenses. I call this immune system maintenance. The best way to fight infection in the long run is to remain healthy and build a robust immune system.

Once you realize that you sick, however, you should take additional steps immediately to lessen the severity and duration of illness, ensure you avoid a trip to the hospital, and limit your exposure to institutional infections. Today, most hospital-based doctors and clinicians are prevented from offering appropriate care due to endemic corruption throughout the medical establishment, so you are often better off treating yourself at home when you catch a respiratory virus.

The most common pathogen is a virus, and the first step in treating a viral infection is blocking viral replication.

We learned this back in 2020 with the rapid spread of the Chinese Wuhan virus. Those who received early treatment with anti-virals like ivermectin and hydroxychloroquine rarely required hospitalization. Many saw their symptoms resolve within 72 hours from the comfort of their homes. This approach can and should be taken with viral infections in general, especially upper respiratory infections.

We are all familiar with the signs: fatigue, muscle weakness or soreness, an itchy sensation in the back of our throat, cough, runny nose. This is how all upper respiratory infections begin. How they end, though, is up to you. If you can prevent the virus from moving into your lungs and multiplying, you are far more likely to suffer only mild symptoms for a few days and then recover.

Although some prescription medications can help, readily available supplements are also effective in reducing viral replication after symptom onset and before the critical 72-hour window closes, after which the infection becomes much harder to treat. Vitamin D, quercetin, and zinc act as a powerful combination, when taken together, to reduce viral replication. Zinc alone does not easily enter human cells, where the virus replicates. It requires an ionophore like quercetin that increases intracellular zinc concentration by a factor of ten. Vitamin D is an excellent overall immune system booster, assisting at every stage of immune response. N-acetyl-cysteine (NAC) replenishes glutathione, a powerful antioxidant and antiviral. Herbs and plants like astragalus, green tea, and elderberry have also been proven effective in treating viral infections.

Keeping a simple one stop go-to supplement kit on hand that you can turn to the moment you develop symptoms is a smart way to prepare yourself and your family for the next time you get sick. I have found one product that includes all the ingredients  above, along with over a dozen other immune system boosters, made specifically for use with acute infections.

Below is a link to my acute infection plan I provide my patients. I am now sharing it with my Substack subscribers. To access the plan, you must first create a free patient account at Fullscript by entering your name and email address: Dr. Mark McDonald’s Fullscript dispensary