Giant horsetail / Cola de caballo

Safety information

Toxicity: Equisetum contains thiaminase, which breaks down thiamine (vitamin B1); chronic use risks thiamine deficiency (neurological/hepatic harm). Few in-vivo toxicity studies; no consensus non-toxic dose. Heat (~100 C), alcohol and alkaline processing inactivate thiaminase, so properly prepared teas/tinctures are preferred.

Contraindications: Pregnancy and lactation (insufficient data); thiamine deficiency or alcoholism (thiaminase risk); pre-existing electrolyte imbalance/heart or kidney disease (diuretic effect); avoid chronic/high-dose use.

Interactions: Additive fluid/electrolyte loss with diuretics; possible additive potassium loss; caution with lithium (diuretic-type herbs can raise lithium levels); may compound thiamine depletion with alcohol.

Pregnancy & breastfeeding: Pregnancy and lactation: insufficient data — avoid.