diff --git a/lagent/llms/openai.py b/lagent/llms/openai.py
index ffbd1b3..1fedcf2 100644
--- a/lagent/llms/openai.py
+++ b/lagent/llms/openai.py
@@ -19,6 +19,7 @@
 warnings.simplefilter('default')
 
 OPENAI_API_BASE = 'https://api.openai.com/v1/chat/completions'
+OPENAI_API_BASE = os.getenv('OPENAI_API_BASE', OPENAI_API_BASE)
 
 
 class GPTAPI(BaseAPILLM):
@@ -903,6 +904,12 @@ def generate_request_data(self,
                     **gen_params
                 }
             }
+        elif 'llama' in model_type.lower():
+            data = {
+                'model': model_type,
+                'messages': messages,
+                **gen_params
+            }
         else:
             raise NotImplementedError(
                 f'Model type {model_type} is not supported')