Garlic: There is some evidence that certain garlic preparations may modestly lower blood pressure in people with hypertension, but the evidence isn’t strong enough to replace medical treatment. �
NCCIH +1
Oregano: It contains compounds with antioxidant and antimicrobial activity in laboratory studies, but that does not mean eating oregano treats diseases in people.
There is no good evidence that doctors are hiding a garlic-and-oregano cure or that this mixture treats conditions such as cancer, fatty liver, parasites, arthritis, or obesity.
Garlic supplements can also interact with medicines and may increase bleeding risk. �
NCCIH
So: garlic and oregano are fine as part of a normal diet, but this viral claim greatly exaggerates their medical benefits.