diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index fb41245579d..6dfaffff681 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -8964,7 +8964,7 @@ abstract class CommonObject
 	 * @param float		$unitPrice		 Product unit price
 	 * @param float		$discountPercent Line discount percent
 	 * @param int		$fk_product		 Product id
-	 * @return	float                    Return integer <0 if KO, buyprice if OK
+	 * @return float|int                 Return buy price if OK, integer <0 if KO
 	 */
 	public function defineBuyPrice($unitPrice = 0.0, $discountPercent = 0.0, $fk_product = 0)
 	{