diff --git a/backend/open_webui/routers/ollama.py b/backend/open_webui/routers/ollama.py
index 4fca10e1f..9314c8bfc 100644
--- a/backend/open_webui/routers/ollama.py
+++ b/backend/open_webui/routers/ollama.py
@@ -26,7 +26,7 @@ from fastapi import (
 )
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import StreamingResponse
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, validator
 from starlette.background import BackgroundTask
 
 
@@ -936,10 +936,19 @@ async def generate_completion(
 
 class ChatMessage(BaseModel):
     role: str
-    content: str
+    content: Optional[str] = None
     tool_calls: Optional[list[dict]] = None
     images: Optional[list[str]] = None
 
+    @validator("content", pre=True)
+    @classmethod
+    def check_at_least_one_field(cls, field_value, values, **kwargs):
+        # Raise an error if both 'content' and 'tool_calls' are None
+        if field_value is None and ("tool_calls" not in values or values["tool_calls"] is None):
+            raise ValueError("At least one of 'content' or 'tool_calls' must be provided")
+
+        return field_value
+
 
 class GenerateChatCompletionForm(BaseModel):
     model: str