Sage is safe for most people when used as a cooking herb in normal amounts. A pinch in your pasta sauce or a few leaves in stuffing poses no health risk. The concerns around sage come from consuming it in large quantities, drinking concentrated teas regularly, taking supplements, or ingesting sage essential oil, which is a different product entirely from the dried leaves in your spice rack.
The key factor is a natural compound in sage called thujone, which can cause neurological problems at high doses. But the amount matters enormously, and most people never come close to a harmful level through ordinary cooking.
Why Thujone Is the Main Concern
Common sage (the kind you buy at the grocery store) naturally contains thujone, a compound that in large amounts can cause seizures, hallucinations, and mental confusion. These symptoms were historically associated with heavy absinthe drinking in the 19th century, since wormwood, absinthe’s key ingredient, also contains thujone.
Risk assessments have proposed a safe daily intake of about 0.11 mg of thujone per kilogram of body weight. For a 150-pound person, that works out to roughly 7.5 mg per day. Researchers estimate it would take somewhere between 2 and 20 cups of sage tea daily to reach even that conservative limit, depending on the strength of the brew. So a cup of sage tea here and there, or sage seasoning on your roast chicken, falls well within safe territory.
Where people run into trouble is with prolonged, heavy use of sage tea (multiple cups every day for weeks) or with sage supplements that concentrate the plant’s compounds far beyond what you’d get from food.
Sage Essential Oil Is Genuinely Dangerous
This is the most important distinction to understand. Sage essential oil is not the same as dried sage leaves, and swallowing it can be toxic. Essential oils are highly concentrated plant extracts. As little as 2 to 3 milliliters of certain essential oils can cause toxicity in children, and 5 to 15 milliliters can be toxic in adults.
Symptoms of essential oil poisoning typically appear within one hour and can include nausea, vomiting, dizziness, drops in blood pressure, and in serious cases, seizures and loss of consciousness. Sage essential oil is meant for aromatherapy diffusers or diluted topical use. It should never be swallowed, added to food, or put in tea. If you see advice online suggesting you ingest essential oils, ignore it.
Pregnancy and Breastfeeding Risks
Sage carries specific risks during pregnancy. The thujone in sage can raise blood pressure, which is particularly concerning during the second and third trimesters. In women already prone to high blood pressure during pregnancy, sage consumption may increase the risk of the placenta separating prematurely from the uterine wall. There is also concern that thujone may increase miscarriage risk, especially with frequent consumption during the first trimester.
Sage has also traditionally been used to reduce breast milk supply, which is why breastfeeding mothers are generally advised to avoid it in medicinal quantities. Using a light sprinkle in cooking is unlikely to cause problems, but concentrated forms like teas, tinctures, or supplements are worth avoiding during pregnancy and breastfeeding.
Blood Sugar Interactions
Sage has a notable blood sugar lowering effect. Animal studies have found it has potent hypoglycemic activity, meaning it can significantly reduce blood glucose levels. For most people, this is neutral or even beneficial. But if you take medication to manage diabetes and you start drinking sage tea regularly or taking sage supplements, the combined effect could push your blood sugar too low. If you’re on blood sugar medication, it’s worth being aware of this interaction before adding sage to your daily routine in concentrated forms.
Burning Sage and Indoor Air Quality
Smudging, the practice of burning dried sage bundles, is a separate question from eating it. According to the National Institute of Environmental Health Sciences, burning sage indoors produces particulate matter that can be harmful to the lungs, just like burning incense, candles, or anything else. Indoor combustion can also release formaldehyde, carbon monoxide, and other contaminants.
In moderation and with good ventilation, occasional smudging is unlikely to cause harm for most people. But burning sage frequently in a closed room, especially if you have asthma or other respiratory conditions, can irritate your airways and degrade your indoor air quality. If you smudge regularly, open a window during and after.
How Much Sage Is Actually Safe
For everyday cooking, sage is completely fine. Seasoning a dish with a teaspoon or two of dried sage is nowhere near a concerning dose. An occasional cup of sage tea is also safe for most adults who aren’t pregnant or on blood sugar medication.
The risk increases with concentration and frequency. Here’s a practical breakdown:
- Cooking with dried sage leaves: Safe in any normal culinary amount.
- Sage tea (occasional): Safe for most adults. One or two cups a day is well within proposed limits.
- Sage tea (daily, long-term): Worth being cautious, especially at higher concentrations. Avoid drinking many cups per day for extended periods.
- Sage supplements: Use with caution, since doses are concentrated. Follow the label and be aware of interactions with diabetes medications.
- Sage essential oil (ingested): Never safe to swallow. This is a concentrated extract that can cause poisoning.
The Codex Alimentarius Commission has set maximum thujone limits for commercially prepared sage products at 25 mg per kilogram in food containing sage and 250 mg per kilogram in sage stuffings, which gives manufacturers a safety framework. For home cooking, you’d have to eat an impractical amount of sage to approach these levels.
In short, sage is a safe and flavorful herb for the vast majority of people. The problems arise at the extremes: essential oil ingestion, heavy daily tea consumption over long periods, and use during pregnancy. If you’re adding it to your cooking, there’s nothing to worry about.