Hai Zao (海藻) — Seaweed / Sargassum | TCM Herb Guide

At a Glance

• Herb: Hai Zao
• Chinese name: 海藻 (Hǎi Zǎo)
• Latin name: Sargassum
• Nature: Cold
• Taste: Bitter / Salty
• Meridian: Liver / Kidney / Stomach
• Category: Herbs that Transform Phlegm and Stop Coughing
• Introduction: Hai Zao (海藻), Sargassum, is the dried whole plant of Sargassum pallidum or S. fusiforme, a brown marine alga harvested from China’s coastal waters. In TCM it resolves phlegm, softens hardness, and disperses nodules — primarily for goiter, scrofula, and testicular swelling from phlegm accumulation. Its high iodine content directly addresses iodine-deficiency goiter, while fucoidan polysaccharides exhibit anti-tumor, anticoagulant, and lipid-lowering properties in modern research.

Action

• Resolves phlegm and softens hardness
• Disperses nodules and dissipates masses
• Promotes urination and reduces edema
• Clears heat and reduces swelling

Clinical Application

• Goiter (ying liu) from phlegm-qi accumulation — combines with Kun Bu, Xia Ku Cao, Zhe Bei Mu
• Scrofula (luo li): cervical lymph node enlargement — combines with Xuan Shen, Bei Mu, Mu Li
• Testicular swelling and pain from phlegm-cold accumulation — combines with Kun Bu, Ju He, Chuan Lian Zi
• Edema from fluid retention — combines with Ze Xie, Fu Ling, Che Qian Zi
• Hyperlipidemia and arteriosclerosis (modern use) — used as dietary supplement

Precautions

• Dosage: 6–12 g in decoction
• Incompatible with Gan Cao (甘草) — listed in the 18 incompatibilities (十八反); classical prohibition, though some modern formulas combine them cautiously
• Contraindicated in spleen deficiency with cold-damp patterns
• High iodine — use with caution in hyperthyroidism or iodine-sensitive patients
• Avoid in pregnancy without guidance

Formula

• Hai Zao Yu Hu Tang (海藻玉壶汤): Hai Zao, Kun Bu, Zhe Bei Mu, Ban Xia, Chen Pi, Qing Pi, Dang Gui, Chuan Xiong, Lian Qiao, Gan Cao — resolves phlegm, softens hardness, treats goiter
• Xiao Luo Wan (消瘰丸): Xuan Shen, Mu Li, Bei Mu — with Hai Zao and Kun Bu added for scrofula
• Ju He Wan (橘核丸): includes Hai Zao to soften hardness in testicular swelling

Combinations

• Seaweed (海藻) + Kelp (昆布) + Fritillary Bulb (贝母) → Hai Zao Yu Hu Tang (海藻玉壶汤) basis: resolve phlegm, soften hardness; goiter and thyroid nodules
• Seaweed (海藻) + Oyster Shell (牡蛎) + Scrophularia Root (玄参) → soften hardness, clear heat; scrofula and lymph node swelling
• Seaweed (海藻) + Selfheal Spike (夏枯草) + Forsythia Fruit (连翘) → clear heat, resolve phlegm; thyroid nodules and lipomas
• Seaweed (海藻) + Sparganium Rhizome (三棱) + Zedoary Rhizome (莪术) → break stasis, dissolve masses; abdominal masses (zheng jia)
• Note: Seaweed (海藻) + Pinellia Rhizome (半夏) — traditionally contraindicated per the Eighteen Incompatibilities (十八反)

Pharmacological Effects

• Antithyroid
  • iodine content regulates thyroid
• Anticoagulant
  • fucoidan
• antitumor; anti-inflammatory; antihyperlipidemic; antiviral; softens lymph node and goiter enlargements; diuretic

Classic Description

• Shen Nong Ben Cao Jing (《神农本草经》): ‘Governs goiter and tumor qi, nodules below the neck, breaks and disperses bound qi, carbuncle swelling, firm accumulation masses in the abdomen, gurgling in the abdomen, and drains the twelve types of water swelling.’
• Ben Cao Gang Mu (《本草纲目》): ‘Seaweed: salty flavor moistens and descends; cold nature drains heat and leads water; hence it disperses goiter and tumor, scrofula nodules, and firm accumulations from yin sores.’
• Ming Yi Bie Lu (《名医别录》): ‘Treats skin accumulation, sudden collapse of sores, retained qi with heat binding, and promotes urination.’
• Ben Cao Bei Yao (《本草备要》): ‘Softens hardness, dissolves phlegm, promotes urination, drains heat; treats goiter, scrofula nodules, masses, hernia qi, water edema, and leg qi.’