diff --git a/src/streams.h b/src/streams.h
index 0fc6135a6a793..a50fe4e859d77 100644
--- a/src/streams.h
+++ b/src/streams.h
@@ -240,7 +240,9 @@ class CDataStream
     CDataStream& ignore(int nSize)
     {
         // Ignore from the beginning of the buffer
-        assert(nSize >= 0);
+        if (nSize < 0) {
+            throw std::ios_base::failure("CDataStream::ignore(): nSize negative");
+        }
         unsigned int nReadPosNext = nReadPos + nSize;
         if (nReadPosNext >= vch.size())
         {