diff --git a/google/generativeai/types/content_types.py b/google/generativeai/types/content_types.py
index e6503ed63..ce7b3e59e 100644
--- a/google/generativeai/types/content_types.py
+++ b/google/generativeai/types/content_types.py
@@ -189,6 +189,9 @@ def is_content_dict(d):
 
 
 def to_content(content: ContentType):
+    if not content:
+        raise ValueError("content must not be empty")
+
     if isinstance(content, Mapping):
         content = _convert_dict(content)