"Stop me if you need a medical consultation," reads a large sticker on the rear window of Sami Yahya Al Hajj's four-wheel drive, alongside a cartoon figure of the bearded doctor wearing his square spectacles.
As he offers diagnoses and prescriptions to the poor, the doctor's phone chirps with messages and calls from patients who cough and splutter as they explain their ailments.
Hajj said he started giving free consultations via social media but then wanted to reach to those without access to such technology.
"I thought about the poor and those in need on the streets who cannot get medical advice or don’t have the money for it,” he told AFP.
Yemen is facing what the United Nations calls the world’s worst humanitarian crisis. A war between the government and Houthi rebels has killed tens of thousands and displaced four million people.
Many Yemenis are afflicted by malnutrition and disease but the country’s healthcare system has all but collapsed, leaving it extremely vulnerable to the spread of the COVID-19 respiratory disease.
In the rebel-held capital of Sanaa, Hajj is flagged down by a man driving alongside his car.
"My wife for the past week or two...” calls out the man, before Hajj asks him to pull over.
After a roadside consultation, Hajj prescribes a course of vitamins.
"We doctors are on the frontlines of this current pandemic, and we must disseminate advice even outside medical facilities,” said Hajj, who has nearly 18,000 followers on Facebook.
"We must safeguard and maintain the health of the poor, because their health is part of the whole community,” he said.
Yemen’s government has officially recorded hundreds of coronavirus cases, including 112 deaths.
But according to the United Nations, testing and reporting remain limited and it is likely that most areas in the country have been impacted.
"Here is a Yemeni doctor treating the poor for free on the streets,” said one of Hajj’s supporters in a Facebook post hailing his "noble and beautiful” contribution.
"I wish all Yemeni doctors would do the same in the current situation we are in