diff --git a/fast_plotter/plotting.py b/fast_plotter/plotting.py
index 5594caa..15a0ef4 100644
--- a/fast_plotter/plotting.py
+++ b/fast_plotter/plotting.py
@@ -374,10 +374,12 @@ def plot_1d_many(df, prefix="", data="data", signal=None, dataset_col="dataset",
               (in_df_data, plot_data, kind_data, data_legend, "plot_data"),
               (in_df_signal, plot_signal, kind_signal, "Signal", "plot_signal"),
               ]
+    kwargs.setdefault("is_null_poissonian", False)
     for df, combine, style, label, var_name in config:
         if df is None or len(df) == 0:
             continue
-        merged = _merge_datasets(df, combine, dataset_col, param_name=var_name, err_from_sumw2=err_from_sumw2)
+        merged = _merge_datasets(df, combine, dataset_col, param_name=var_name, err_from_sumw2=err_from_sumw2,
+                                 is_null_poissonian=kwargs['is_null_poissonian'])
         actually_plot(merged, x_axis=x_axis, y=y, yerr=yerr, kind=style,
                       label=label, ax=main_ax, dataset_col=dataset_col,
                       dataset_colours=dataset_colours,
@@ -392,9 +394,11 @@ def plot_1d_many(df, prefix="", data="data", signal=None, dataset_col="dataset",
     if summary.startswith("ratio"):
         main_ax.set_xlabel("")
         summed_data = _merge_datasets(
-            in_df_data, "sum", dataset_col=dataset_col, err_from_sumw2=err_from_sumw2)
+            in_df_data, "sum", dataset_col=dataset_col, err_from_sumw2=err_from_sumw2,
+            is_null_poissonian=kwargs['is_null_poissonian'])
         summed_sims = _merge_datasets(
-            in_df_sims, "sum", dataset_col=dataset_col, err_from_sumw2=err_from_sumw2)
+            in_df_sims, "sum", dataset_col=dataset_col, err_from_sumw2=err_from_sumw2,
+            is_null_poissonian=kwargs['is_null_poissonian'])
         if summary == "ratio-error-both":
             error = "both"
         elif summary == "ratio-error-markers":
@@ -411,7 +415,8 @@ def plot_1d_many(df, prefix="", data="data", signal=None, dataset_col="dataset",
     return main_ax, summary_ax
 
 
-def _merge_datasets(df, style, dataset_col, param_name="_merge_datasets", err_from_sumw2=False):
+def _merge_datasets(df, style, dataset_col, param_name="_merge_datasets", err_from_sumw2=False,
+                    is_null_poissonian=False):
     if style == "stack":
         df = utils.stack_datasets(df, dataset_level=dataset_col)
     elif style == "sum":
@@ -419,7 +424,7 @@ def _merge_datasets(df, style, dataset_col, param_name="_merge_datasets", err_fr
     elif style:
         msg = "'{}' must be either 'sum', 'stack' or None. Got {}"
         raise RuntimeError(msg.format(param_name, style))
-    utils.calculate_error(df, do_rel_err=not err_from_sumw2)
+    utils.calculate_error(df, do_rel_err=not err_from_sumw2, is_null_poissonian=is_null_poissonian)
     return df
 
 
diff --git a/fast_plotter/utils.py b/fast_plotter/utils.py
index b765452..1cfbf57 100644
--- a/fast_plotter/utils.py
+++ b/fast_plotter/utils.py
@@ -91,7 +91,7 @@ def split_data_sims(df, data_labels=["data"], dataset_level="dataset"):
     return split_df(df, first_values=data_labels, level=dataset_level)
 
 
-def calculate_error(df, sumw2_label="sumw2", err_label="err", inplace=True, do_rel_err=True):
+def calculate_error(df, sumw2_label="sumw2", err_label="err", inplace=True, do_rel_err=True, is_null_poissonian=False):
     if not inplace:
         df = df.copy()
     if do_rel_err:
@@ -105,6 +105,10 @@ def calculate_error(df, sumw2_label="sumw2", err_label="err", inplace=True, do_r
         elif not do_rel_err and sumw2_label in column:
             err_name = column.replace(sumw2_label, err_label)
             df[err_name] = np.sqrt(df[column])
+        else:
+            continue
+        if is_null_poissonian:
+            df[err_name] = df[err_name].apply(lambda x: x if x > 1.15 else np.sqrt(1.15**2+x**2))
     if not inplace:
         return df