diff --git a/stdlib/Random/docs/src/index.md b/stdlib/Random/docs/src/index.md
index faf80ced447df9..8821fe322ac947 100644
--- a/stdlib/Random/docs/src/index.md
+++ b/stdlib/Random/docs/src/index.md
@@ -26,6 +26,9 @@ unbounded integers, the interval must be specified (e.g. `rand(big.(1:6))`).
 Additionally, normal and exponential distributions are implemented for some `AbstractFloat` and
 `Complex` types, see [`randn`](@ref) and [`randexp`](@ref) for details.
 
+!!! warn
+    Because the precise way in which random numbers are generated is considered an implementation detail, bug fixes and speed improvements may change the stream of numbers that are generated after a version change. Relying on a specific seed or generated stream of numbers during unit testing is thus discouraged - consider testing properties of the methods in question instead.
+
 ## Random numbers module
 ```@docs
 Random.Random