Chimarrão

Tree, bush. Dried leaves are used in infusion (social consumption of mate). Highly consumed in Uruguay, Argentina, Paraguay, southern Brazil, Bolivia and Chile. Contains alkaloids, xanthines (caffeine 2%, theobromine 0.2%, theophylline 0.05%), tannins, flavonoids. Attributed properties are: mood stimulant, diuretic, bronchodilator, and vasoconstrictor. Indication of Commission E of the German Ministry of Health ^{(Blumenthal 1998)}: physical and mental fatigue.

One 500 ml chimarrão (mate) "cuia" (gourd bowl) contains 135 mg of caffeine. One cuia of tererê contains 85 mg of caffeine. One cup of 182 ml of tea ("cooked mate") contains 13 mg of caffeine ^{(Markowicz 2005)}. An average consumer of mate eats 100 to 200 mg of caffeine a day, although consumption can be as high as 1 gram a day. ^{(Pepino 2004, Vázquez 1986)}

At the date of the last update, the authors did not find any published data on its excretion in breast milk.

During the Covid-19 pandemic (2020-21) in Argentina, women during the postpartum period increased their consumption of caffeinated beverages; yerba mate intake was associated with a better psychological state and greater self-efficacy in breastfeeding, as opposed to coffee intake^{. (Miranda 2023)}

Neonatal withdrawal syndrome has been published after chronic maternal consumption of mate. ^{(Martín 2007)}

Excessive consumption (more than 300 mg of caffeine per day) has been associated with irritability and insomnia in infants ^{(Santos 2012, Martín 2007, Clement 1989, Rustin 1989)}, low levels of iron in breast milk with anemia in infants (Muñoz 1988) and Raynaud's phenomenon of the nipple in the mother. ^{(McGuinness 2013)}

One study found no problems in infants whose mothers consumed 500 mg of caffeine daily for 5 days ^{(Ryu 1985)}. There is not enough evidence on what the maximum recommended amount of caffeine is during breastfeeding. ^{(McCreedy 2018)}

There is no evidence of its effectiveness as a galactogogue; due to its caffeine content it seems prudent to moderate its consumption during breastfeeding ^{(Pepino 2004)}. The best galactogogue is breastfeeding on frequent demand and with correct technique. ^{(ABM 2018 and 2011, Mannion 2012)}

Precautions when taking herbal teas or plant preparations ^{(Anderson 2017, Powers 2015, Posadzki 2013, Efferth 2011, Kopec 1999, Hsu 1995)}:

Make sure they are from a reliable source. Poisonings have occurred due to confusion of one plant with another with toxic properties ^{(Hsu 1995)}, poisonings due to containing heavy metals extracted from the soil and food poisoning due to contamination with bacteria or fungi.

Do not take in excess. Follow the recommendations of professional experts in herbal medicine. “Natural” products are not good in any quantity: plants contain active substances from which a large part of our traditional pharmacopoeia has been obtained and can cause poisoning or act as endocrine disruptors because they contain phytoestrogens ^{(Powers 2015)} if they are consumed in an exaggerated quantity or time. An excessive consumption of mate (more than one liter a day) increases the risk of oro-pharyngeal-laryngeal-esophageal cancer. ^{(Mello 2018)}