Within an hour of drinking the tea made from the leaves supplied by the same San Francisco herbalist in Chinatow, a woman in her 50s and man in his 30s became critically ill.  

Both victims quickly developed weakness, and then life-threatening abnormal heart rhythms, requiring resuscitation and intensive hospital care...

The male victim recovered and was released earlier this month, while the female victim remained in the hospital and died on March 18, 2017.
(via "WOMAN DIES AFTER DRINKING TOXIC TEA FROM SAN FRANCISCO'S CHINATOWN"

The store's name is Sun Wing Wo Trading Company - the Health Deparment's environmental health inspectors removed the product from the shelves.  A plant-based toxin named Aconite was found in lab tests of the patients and the tea samples they provided.

RELATED: Two hospitalized by poison tea from San Francisco's Chinatown

Aconite, via WebMD: 

Aconite is a plant. The root is used as medicine. However, aconite contains some poisonous chemicals. In Hong Kong, aconite is the most common cause of severe poisoning from herbs. In Asia, toxicity is usually related to the use of aconite in traditional medicines. In western countries, aconite poisoning is usually associated with consuming the plant.

...

SIDE EFFECTS:

Do not use aconite. Aconite root is UNSAFE when taken by mouth. All species of the plant are dangerous, and so are processed products. Aconite contains a strong, fast-acting poison that causes severe side effects such as nausea, vomiting, weakness or inability to move, sweating, breathing problems, heart problems, and death.

Some people use aconite in a cream or lotion that is applied to the skin. This practice is also dangerous. The poisons in aconite can be absorbed through the skin, causing severe side effects.