GlaxoSmithKline PLC is investigating claims its employees bribed doctors in Jordan and Lebanon by offering perks such as flexible travel arrangements and free samples that doctors could sell on, according to emails reviewed by The Wall Street Journal.

The probe is the latest to emerge at the British pharmaceutical giant, which has opened a broad investigation into its practices in the Middle East. Earlier this month, the Journal reported Glaxo had received emails alleging its employees had bribed doctors in Iraq. Separately, Chinese and Polish authorities are investigating alleged bribery of doctors by Glaxo representatives in those markets.

In a statement, Glaxo said that it takes all bribery allegations seriously, has zero tolerance for unethical or illegal behavior, and has strict controls in place with regard to compliance matters and antibribery and corruption.

"In total, we employ around 200 people in Jordan, Lebanon and Iraq in our pharmaceuticals operations and these allegations relate to a small number of individuals in these countries," the statement said.

Glaxo said that it is confident it doesn't have a systemic issue with unethical behavior. The company reported 161 breaches of its sales and marketing policies last year, a number it says is similar to its peers.

Glaxo has said it has launched an internal investigation into its operations in the United Arab Emirates, Qatar, Bahrain, Oman, Kuwait, Lebanon, Syria, Jordan and Iraq.

Chinese authorities last summer accused Glaxo of bribing doctors and have opened their own probe. Glaxo has said it appears that some its senior staff in China may have broken the law and that it is cooperating with the investigation.Ã

This week, Poland's anti corruption bureau said it is investigating alleged bribery of doctors by Glaxo employees between 2010 and 2012 and has so far charged 13 people. Glaxo said an internal investigation into the matter found evidence of inappropriate behavior by just one employee, whom it disciplined in 2011.

A person first contacted Glaxo in December about its practices in Jordan and Lebanon. This person detailed the alleged bribery in a series of emails to company representatives, reviewed by the Journal.

Glaxo sales representatives allegedly bribed doctors in Jordan to prescribe Glaxo drugs by issuing free samples that the doctors were then allowed to sell on, according to the emails.

Glaxo representatives also allegedly permitted Jordanian doctors to bring their spouses on business trips that Glaxo paid for, according to the emails. Doctors were issued with business-class tickets to attend conferences but would exchange them at travel agencies for two economy-class tickets, allowing their spouses or other family members to come along free, a practice local Glaxo employees were aware of, according to the emails.

Glaxo said that it is against company policy to allow airplane tickets to be exchanged for tickets of a lower value or refunded.

The emails allege Glaxo sales representatives gave doctors in Jordan up to 60 free samples of its vaccine Synflorix, which they then sold on at up to $70 a vial.

In Lebanon, Glaxo employees allegedly gave doctors free Synflorix vials as part of an incentive scheme to get them to prescribe the vaccine and not its competitors, another email to company representatives said. In both countries, Glaxo made payments to "key opinion-leader" doctors--influential and leading practitioners in their field--for lectures and other speaking engagements that may not have taken place, the emails allege, in return for them prescribing more Glaxo drugs.

Glaxo said it has reinforced governance requirements in the nine Middle East countries its investigations have focused on, including payments to doctors and travel agencies, provision of samples and processes around public-tender submissions, such as the awarding of government vaccine contracts, as well as putting a temporary stop to interactions with government officials in the region where they involve a payment.

Glaxo said in December it was stopping all payments to doctors globally to attend conferences or speak about its drugs--a policy it expects to be in place around the world by 2016.

Write to Hester Plumridge at Hester.Plumridge@wsj.com and Christopher Matthews at christopher.matthews@wsj.com

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