Seaweeds contain large amounts of mucilage and minerals, including iodine which appears in variable amounts that can be significant, in such a way that it may be a cause a hyperthyroidism-like disease (anxiety, insomnia, tachycardia, palpitations).It may also contain heavy metals, being a species of seaweed with a high ability of contamination by toxic products. Seaweed consumption increases levels of iodine in plasma and breast milk.There have been reports of hypothyroidism in infants whose mothers have included in their diet important quantities of seaweed. There is no evidence of effectiveness on increasing milk production. The most effective method to increase milk production should be done by strengthening maternal self-confidence, evaluate and correct problems along with an effective support to breastfeeding mothers. It is recommended to obtain information on the composition of any particular algae and avoid it or use it in very moderate amount in case of iodine content would be important.