diff --git a/math/papilo/Portfile b/math/papilo/Portfile
index 12b602241df85..ced207bf0291a 100644
--- a/math/papilo/Portfile
+++ b/math/papilo/Portfile
@@ -6,10 +6,13 @@ PortGroup               cmake 1.1
 PortGroup               github 1.0
 PortGroup               compiler_blacklist_versions 1.0
 PortGroup               compilers 1.0
+PortGroup               conflicts_build 1.0
 
 # Boost 1.76 has a bug in multiprecision library,
 # which leads to including x86 header on powerpc.
 boost.version           1.81
+# If this port is active, wrong headers get picked.
+conflicts_build         boost
 
 # NOTE: PaPILO is a header-based library, please bump all dependent ports on update
 github.setup            scipopt papilo 2.3.1 v