diff --git a/dumux/material/fluidsystems/1pfluidsystem.hh b/dumux/material/fluidsystems/1pfluidsystem.hh
index b243eebc737401d8d70fe6d8f2f71c57eee50a13..d3cc6840188c42eeec75044c8757f6df7326abf0 100644
--- a/dumux/material/fluidsystems/1pfluidsystem.hh
+++ b/dumux/material/fluidsystems/1pfluidsystem.hh
@@ -298,7 +298,7 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
+     * \f[ J = - D \mathbf{grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
diff --git a/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh b/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh
index 8294df10a4582060543f8f2f34b7cb4050f8ebf4..70b21a293b0d5b41866e2b977445639ccfbc971b 100644
--- a/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh
+++ b/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh
@@ -331,7 +331,7 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
+     * \f[ J = - D \mathbf{grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
diff --git a/dumux/material/fluidsystems/basefluidsystem.hh b/dumux/material/fluidsystems/basefluidsystem.hh
index afa62d2c2bf3afe84b1bdaed290b5f6d981fbd41..ee81046e220b5abe8bf78e6d9a62f23f7f27a007 100644
--- a/dumux/material/fluidsystems/basefluidsystem.hh
+++ b/dumux/material/fluidsystems/basefluidsystem.hh
@@ -89,7 +89,7 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
+     * \f[ J = - D \mathbf{grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
diff --git a/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh b/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh
index cf026bb819120351493908b3f0230739ca48234a..d1f016892fc0a37052217abaf5cdb46540f7536a 100644
--- a/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh
+++ b/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh
@@ -458,7 +458,7 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
+     * \f[ J = - D \mathbf{grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
diff --git a/dumux/material/fluidsystems/spe5fluidsystem.hh b/dumux/material/fluidsystems/spe5fluidsystem.hh
index 49b0753caea3b06d26b451e21c0640189a7d8734..825f759a4c9d835430e1db0d1bf94acceda9d8ef 100644
--- a/dumux/material/fluidsystems/spe5fluidsystem.hh
+++ b/dumux/material/fluidsystems/spe5fluidsystem.hh
@@ -441,7 +441,7 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \grad \mu_\kappa \f]
+     * \f[ J = - D grad \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the