BANGOR, Maine — A health care company that operates walk-in clinics in five states that specialize in qualifying people to use medical marijuana recently expanded into Maine, with locations in Bangor, Augusta, Biddeford, and a fourth planned for Auburn.

“There is such a need in the state. There are very few practitioners writing medical marijuana certifications,” Jenna McDonald, general manager for Canna Care Docs, a division of Virginia-based Med-Eval Corp., said Friday.

The walk-in clinics are relatively new to Maine, where voters first approved medical marijuana in 1999 allowing patients to grow their own supply or select a caregiver to grow it for them. In 2009, the law was expanded to include more permitted medical conditions and to allow patients to buy from eight nonprofit, government-sanctioned clinics and marijuana cultivation centers as long as a licensed medical professional certifies their need for the drug.

While there are doctors and nurse practitioners writing medical marijuana certifications in Maine, “we’re the only ones doing it on a walk-in basis,” McDonald said.

It works like this: A person walks into the clinic, pays $200, is seen by a medical professional who takes his or her vital signs and asks questions about the person’s health history. Depending on the answers, the person receives education about the medical use of marijuana, including possible side effects, and a document qualifying the person to purchase medical marijuana. A portion of the funds are returned to the patient if the certification is not issued, Bangor Canna Care Docs employee Janelle Kelley said Friday.

“It takes about 45 minutes to do the paperwork, which includes a medical history,” she said. “You need a state-issued ID or driver’s license, not a passport or federal IDs because it’s still illegal federally. If they don’t qualify, they get $150 back. The $50 goes to the [examiner]. If they do get qualified, we don’t charge anything for a six-month follow-up.”

Clinics are staffed with what the company’s website states are “board-certified and licensed medical professionals.”

In Bangor, there are two nurse practitioners seeing patients, Kelley said.

Patients also can also see if they qualify by calling ahead, McDonald said.

The practitioners that work for Canna Care Docs are on a rotating schedule and have full-time jobs outside of the per diem clinic work they do, except for two full-time nurse practitioners who were recently hired, she said.

With the new, expanded services in Maine, Canna Care Docs is “currently writing probably about one-third of the certifications in the state,” McDonald said.

“We started two years ago in Massachusetts, and we started in Maine in August of last year,” she said. “Our first location opened in Biddeford, and Augusta opened in November 2014. We opened Bangor just last month, and we’re opening in Auburn next month.”

Canna Care Docs also operates clinics in Rhode Island, Connecticut, Delaware and the District of Columbia.

The company “is committed to the medicinal value of cannabis” and provides patients access to “a caring, non-judgmental medical professional,” according to its website.

Dedham resident Mark VanHorn was in the Bangor Canna Care Docs office on Friday. He suffered a cracked pelvis during a May 2002 car crash trying to avoid a deer and still has “nightmares with telephone poles coming at me.” He said he never fully recovered, and he suffers from anxiety. He said he has previously self-medicated with marijuana.

“It relaxes me, it takes the pain away, and it allows me to carry on a life,” VanHorn said. “I still take valium for the anxiety, and I want to go totally natural. Pharmaceuticals are bad and all natural is good. That is what I want.”

He had thought about asking his primary care doctor for a certification but decided to turn to Canna Care Docs after he heard how convenient it is to apply.

“Because of the location, I decided to pursue it,” he said while in the waiting room. “It’s very professional in here. It’s very above board.”

He said later in the day that after going through the review process and talking to the nurse practitioner for about 15 minutes, she printed his certification off right there in her office.

Some of the state’s hospitals will not allow their doctors to recommend marijuana because it is banned federally, McDonald said.

Over the years, amendments have been made to Maine’s medical marijuana law to include more medical conditions, eliminate the need for patients to register with the state, and last year, the word “physician” was replaced with “medical provider” to allow nurse practitioners to prescribe the medication, and the definition of prepared marijuana was changed to allow byproducts, including concentrates such as honey oil.

The Bangor Canna Care Docs office, which is open three days per week on Harlow Street, opened its doors at the beginning of April, Kelley said.

“It’s been amazing,” she said of the turnout, which is typically between 14 and 22 patients a day.

To help get the word out about their new walk-in clinics, Canna Care Docs is holding a free veterans screening and certifications from 10 a.m. to 4 p.m. Saturday at its Augusta location, 147 Riverside Drive.

“Getting a recommendation has been a huge problem for veterans,” McDonald said. “Obviously, they can’t get a medical marijuana certification through the VA [Veterans Administration]. There are so many veterans in need, especially in this state.”

Post-traumatic stress disorder, an ailment suffered by some veterans, was added as a qualifying condition for medical marijuana in June 2013.