Table 2. Concentrations of biguanides in colorful herbal pills for diabetes treatment.

Color of herbal pills (samples)	Phenformin	Metformin	Arsenic	Names of the laboratory
Brown or yellow		Undetectable		Institute of Drug Quality Control - HCMC
Green		Undetectable
Soft black herbal balls	Undetectable
Brown for diabetes and renal failure	Undetectable
Brown pills	0.02 mg/ pill
>Yellow pills	24.72 mg/pill
Yellow			23.97 mg/pill
Green			7.98 mg/pill
Red			7.96 mg/pill
Yellow			25.41 mg/pill
Pink	8.48 mg/pill	Undetectable		Institute of Public Health
Green	9.05 mg/pill	Undetectable
Brown	0.005 mg/pill or 28.29 mg/kg	< 3 mg/kg
Brown	0.002 mg/pill	< 3 mg/kg
Green	8.23 mg/pill	Undetectable
Green	37339.61 mg/kg	9472.44 mg/kg
Pink	30770.64 mg/kg	3437.94 mg/kg
Brown	162.48 mg/kg	< 10 mg/kg	0.918 mg/kg
Soft black herbal balls	<10 mg/kg	Undetectable	0.062 mg/kg
Yellow	0.03 mg/pill	Undetectable
Grey	3.7 mg/pill	Undetectable
Brown	0.59%	Undetectable	0.075 mg/kg
Brown	9.72%	Undetectable
Brown	0.005 mg/pill or 28.29 mg/kg	< 3 mg/kg
Green	9.05 mg/pill	Undetectable