diff --git a/README.md b/README.md
index 31adec9d..7401d2b1 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-[![flake8 Lint](https://github.com/fjosw/pyerrors/actions/workflows/flake8.yml/badge.svg)](https://github.com/fjosw/pyerrors/actions/workflows/flake8.yml) [![CI](https://github.com/fjosw/pyerrors/actions/workflows/CI.yml/badge.svg)](https://github.com/fjosw/pyerrors/actions/workflows/CI.yml)[![](https://img.shields.io/badge/python-3.5+-blue.svg)](https://www.python.org/downloads/)
+[![flake8 Lint](https://github.com/fjosw/pyerrors/actions/workflows/flake8.yml/badge.svg)](https://github.com/fjosw/pyerrors/actions/workflows/flake8.yml) [![CI](https://github.com/fjosw/pyerrors/actions/workflows/CI.yml/badge.svg)](https://github.com/fjosw/pyerrors/actions/workflows/CI.yml) [![](https://img.shields.io/badge/python-3.5+-blue.svg)](https://www.python.org/downloads/)
 # pyerrors
 pyerrors is a python package for error computation and propagation of Markov Chain Monte Carlo data.
 It is based on the gamma method [arXiv:hep-lat/0306017](https://arxiv.org/abs/hep-lat/0306017). Some of its features are:
diff --git a/pyerrors/correlators.py b/pyerrors/correlators.py
index 33809267..10bc3b14 100644
--- a/pyerrors/correlators.py
+++ b/pyerrors/correlators.py
@@ -129,6 +129,9 @@ class Corr:
         if self.T % 2 != 0:
             raise Exception("Can not symmetrize odd T")
 
+        if np.argmax(np.abs(self.content)) != 0:
+            print('Warning: correlator does not seem to be symmetric around x0=0.')
+
         newcontent = [self.content[0]]
         for t in range(1, self.T):
             if (self.content[t] is None) or (self.content[self.T - t] is None):
@@ -144,6 +147,9 @@ class Corr:
         if self.T % 2 != 0:
             raise Exception("Can not symmetrize odd T")
 
+        if not all([o.zero_within_error() for o in self.content[0]]):
+            print('Warning: correlator does not seem to be anti-symmetric around x0=0.')
+
         newcontent = [self.content[0]]
         for t in range(1, self.T):
             if (self.content[t] is None) or (self.content[self.T - t] is None):
diff --git a/pyerrors/pyerrors.py b/pyerrors/pyerrors.py
index 947be666..9a0d02c0 100644
--- a/pyerrors/pyerrors.py
+++ b/pyerrors/pyerrors.py
@@ -340,6 +340,9 @@ class Obs:
                 for e_name in self.e_names:
                     print(e_name, ':', self.e_content[e_name])
 
+    def zero_within_error(self):
+        return np.abs(self.value) <= self.dvalue
+
     def plot_tauint(self, save=None):
         """Plot integrated autocorrelation time for each ensemble."""
         if not self.e_names: