diff --git a/README.md b/README.md
index e6cb936..03e6a0b 100644
--- a/README.md
+++ b/README.md
@@ -22,41 +22,21 @@ More on the topic:
 
 ## Installation
 
-Install the core functionality:
 ```bash
 pip install rico
 ```
 
-The core functionality has no dependencies other than the standard Python packages. Optional additional dependencies are required to support the following content types:
-* Plots. Altair, Matplotlib Pyplot and Seaborn are currently supported.
+**rico** has no dependencies other than the standard Python packages.
 
-Install one or several extras to use plots or Markdown in HTML documents.
-
-[Altair](https://altair-viz.github.io/):
-```bash
-pip install rico[altair]
-```
-
-[Matplotlib Pyplot](https://matplotlib.org/):
-```bash
-pip install rico[pyplot]
-```
-
-[Seaborn](https://seaborn.pydata.org/):
-```bash
-pip install rico[seaborn]
-```
+### Deprecated
 
-Install `rico[seaborn]` extra only to use the [seaborn.objects](https://seaborn.pydata.org/tutorial/objects_interface.html) interface. Otherwise install `rico[pyplot]` as the old Seaborn plotting functions return Matplotlib Pyplot Axes objects.
+Optional additional dependencies were required to support the following content types:
+* Plots (`rico[altair]`, `rico[pyplot]`, `rico[seaborn]`).
+* Markdown (`rico[markdown]`).
 
-All extras:
-```bash
-pip install rico[complete]
-```
-
-### Deprecated
+The `rico[complete]` extra incudes all the dependencies above.
 
-There is also the `rico[markdown]` extra. But it's no longer needed and will be removed in version 0.4.0.
+They are no longer needed and will be removed in version 0.4.0.
 
 ## User guide
 
diff --git a/src/rico/_content.py b/src/rico/_content.py
index 7e4fd48..9818ce1 100644
--- a/src/rico/_content.py
+++ b/src/rico/_content.py
@@ -7,6 +7,7 @@
 import io
 from typing import TYPE_CHECKING
 import urllib.request
+import warnings
 import xml.etree.ElementTree as ET
 
 import rico._config
@@ -251,9 +252,14 @@ def __init__(
         """Create an HTML element from a plot object and wrap it in a <div> container.
 
         The supported plot types are the following:
-        - Altair Chart,
-        - Pyplot Axes and Figure,
-        - Seaborn Plot (seaborn.objects interface).
+        - Matplotlib Pyplot Axes and Figure,
+        - [Deprecated] Altair Chart,
+        - [Deprecated] Seaborn Plot (seaborn.objects interface).
+
+        Deprecated:
+            Support of the Seaborn plots in this class/method is deprecated
+            and will be removed in version 0.4.0.
+            Use the rico.Obj or obj.append indstead.
 
         Args:
             obj: The plot object.
@@ -277,10 +283,24 @@ def __init__(
             obj.savefig(stream, format=format, **kwargs)
             image = stream.getvalue()
         elif so is not None and isinstance(obj, so.Plot):
+            warnings.warn(
+                "Support of the Seaborn plots in this class/method is deprecated "
+                    "and will be removed in version 0.4.0. "
+                    "Use the rico.Obj or obj.append indstead.",
+                DeprecationWarning,
+                stacklevel=2,
+            )
             stream = io.StringIO() if format == "svg" else io.BytesIO()
             obj.save(stream, format=format, **kwargs)
             image = stream.getvalue()
         elif alt is not None and isinstance(obj, alt.TopLevelMixin):
+            warnings.warn(
+                "Support of the Altair plots in this class/method is deprecated "
+                    "and will be removed in version 0.4.0. "
+                    "Use the rico.Obj or obj.append indstead.",
+                DeprecationWarning,
+                stacklevel=2,
+            )
             convert = vlc.vegalite_to_svg if format == "svg" else vlc.vegalite_to_png  # type: ignore  # noqa: E501
             image = convert(  # type: ignore
                 obj.to_json(),  # type: ignore