What are the potential adverse effects of consuming clove tea, especially in individuals with pre-existing medical conditions such as diabetes, bleeding disorders, or those who are pregnant or breastfeeding?

Adverse Effects of Clove Tea

Clove tea lacks sufficient safety data in humans, particularly regarding bleeding risk, hypoglycemia in diabetics, and use during pregnancy/breastfeeding, warranting extreme caution in these populations.

Bleeding Risk

• Clove contains eugenol and related compounds that may have anticoagulant properties, theoretically increasing bleeding risk in individuals with bleeding disorders or those taking anticoagulant medications 1
• Patients on antiplatelet therapy (aspirin) or anticoagulants (warfarin, direct oral anticoagulants) should avoid clove tea due to potential additive bleeding effects, similar to precautions with other herbal products 2
• Those scheduled for surgery should discontinue clove tea at least 2 weeks prior due to theoretical bleeding complications 2

Hypoglycemic Effects in Diabetes

• Clove extracts demonstrate significant hypoglycemic activity through PPAR-γ activation, which could potentiate the effects of diabetes medications and cause dangerous hypoglycemia 1
• Active compounds (dehydrodieugenol and dehydrodieugenol B) stimulate glucose-lowering mechanisms that may be additive with metformin, sulfonylureas, or insulin 1
• Diabetic patients consuming clove tea require more frequent blood glucose monitoring and potential medication dose adjustments to avoid hypoglycemic episodes 2, 1
• The hypoglycemic effect is unpredictable due to variable concentrations of active compounds in herbal preparations 1

Pregnancy and Breastfeeding

• Clove tea should be avoided during pregnancy due to lack of safety data and theoretical risks to fetal development 2
• No human studies establish the safety of clove consumption during pregnancy, and the active compounds' placental transfer is unknown 2
• Breastfeeding mothers should avoid clove tea as excretion into breast milk and effects on infants are completely unstudied 2
• Pregnant women with gestational diabetes face compounded risk from unpredictable hypoglycemic effects 2, 3

Gastrointestinal Effects

• Herbal teas, including those containing clove, have been associated with severe gastrointestinal complications including peptic ulcer disease and gastrointestinal bleeding 4
• A documented case report describes life-threatening duodenal ulceration with hemorrhagic shock following herbal tea consumption 4
• Patients with pre-existing peptic ulcer disease or gastroesophageal reflux should avoid clove tea 4

Hepatotoxicity Risk

• While specific data on clove tea hepatotoxicity is limited, concentrated herbal extracts carry documented risk of liver damage 5
• Patients with pre-existing liver disease (cirrhosis, hepatitis) should avoid clove tea due to unknown hepatic metabolism and potential for drug-induced liver injury 2, 5
• Monitoring liver function tests should be considered in patients consuming clove tea regularly 5

Drug Interactions

• Clove tea may interact with multiple medication classes due to its bioactive compounds, though specific interaction data is lacking 5, 4
• Theoretical interactions exist with anticoagulants, antiplatelet agents, diabetes medications, and potentially cytochrome P450-metabolized drugs 2, 5
• Healthcare providers must specifically inquire about herbal tea consumption during medication reconciliation 4

Caffeine-Related Effects (if combined with traditional tea)

• If clove is combined with black or green tea, caffeine-related adverse effects apply 6
• Pregnant women should limit total caffeine intake to 200-300 mg daily (approximately 4-6 cups maximum) 6
• Healthy adults should stay below 400 mg caffeine daily (approximately 8-10 cups of tea) to avoid agitation, anxiety, and sleep disturbance 6

Critical Caveats

• The absence of rigorous human safety studies for clove tea means adverse effects may be underreported and unrecognized 7, 5, 4
• Herbal products marketed as "natural" are not subject to the same safety testing as pharmaceuticals, creating significant knowledge gaps 4
• Concentration of active compounds varies dramatically between preparations, making dose-response relationships unpredictable 5, 1
• Patients often fail to disclose herbal product use to healthcare providers, increasing risk of unrecognized adverse effects and drug interactions 4